Dr. Dita Gratzinger is an academic hematopathologist who studies the microarchitecture of supporting cells in the microenvironment in bone marrow and lymph node pathology. Her publications span the role of the microenvironment in myelodysplastic syndromes, the relationship of cutaneous lymphomas to lymphatic vasculature, and manifestations of immune dysregulation in lymphoid tissues. She co-organized and co-chaired the 2015 workshop on Immunodeficiency and Dysregulation for the Society for Hematopathology/European Association for Haematopathology, and gives a short course on the Bone Marrow Manifestations of Systemic Disease at annual meetings of the United States and Canadian Academy of Pathology. As program director for the hematopathology fellowship at Stanford and as a member of the College of American Pathologists Graduate Medical Education Committee, Dr. Gratzinger foregrounds patient-centered team-based care in pathology training. Dr. Gratzinger received her B.A. from the University of California at Berkeley in 1996, her M.D. and PhD from Yale University in 2003, and completed her anatomic pathology residency, surgical pathology fellowship, and hematopathology fellowship at Stanford University in 2007.
- Anatomic Pathology
Hematopathology fellowship director, Stanford (2015 - Present)
Medical Education:Yale School Of Medicine Office of Student Affairs (2003) CT
Board Certification: Hematology, American Board of Pathology (2008)
Fellowship:Stanford Medicine GME (2007) CA
Residency:Stanford Medicine GME (2006) CA
Residency:Stanford Medicine GME (2005) CA
Fellowship, Stanford University Hospital and Clinic - Anatomic Pathology, Hematopathology (2008)
Board Certification: Anatomic Pathology, American Board of Pathology (2006)
MD, Yale University, Medicine (2003)
PhD, Yale University, Experimental Pathology (2003)
BA, U. of California, Berkeley, Biochemistry (1996)
Current Research and Scholarly Interests
I have research interests in the interaction of hematolymphoid neoplasia with the microenvironment. For example, I use a combination of immunohistochemistry, immunofluorescence and image analysis techniques to evaluate the mesenchymal stromal cell compartment in myelodysplastic syndrome (pre-leukemic bone marrow failure disorder). I also have interests in lymphoma vasculature and the tropism of lymphoma for specific types of vasculature.
Pilot Development of Radiation Free Whole Body Magnetic Resonance (MR) Imaging Technique for Staging Children With Cancer
A research study on the diagnosis of spread of disease for children who have been diagnosed with solid tumors using a new whole body imaging technique and a new MR contrast agent (ferumoxytol). Standard tests that are used to determine the extent and possible spread of a child's disease include magnetic resonance (MR) imaging, computed tomography (CT), Positron Emission Tomography (PET) as well as bone scanning, and metaiodobenzylguanidine (MIBG) scanning. The purpose of this study is to determine if newer imaging tests referred to as whole body diffusion-weighted MR and whole body PET/MR can detect the extent and spread of the disease as accurately or even better as the standard tests (CT, MR and/or PET/CT). The advantage of the new imaging test is that it is associated with no or significantly reduced radiation exposure compared to standard CT and PET/CT imaging tests. The results of whole body MR and PET/MR will be compared with that of the conventional, standard imaging studies for tumor detecting.
- Independent Studies (5)
Graduate and Fellowship Programs
Hematopathology (Fellowship Program)
T- and NK-Cell Lymphomas and Systemic Lymphoproliferative Disorders and the Immunodeficiency Setting 2015 SH/EAHP Workshop Report-Part 4
AMERICAN JOURNAL OF CLINICAL PATHOLOGY
2017; 147 (2): 188-203
The 2015 Workshop of the Society for Hematopathology/European Association for Haematopathology aimed to review immunodeficiency-related T- and natural killer (NK)-cell lymphoproliferations.The Workshop Panel reviewed 88 T- or NK-cell lymphoproliferations and rendered consensus diagnoses.Hyperplasias of T-cell subsets may be clonal; retained architecture and the clinical setting support a benign diagnosis. Specific associations include hepatosplenic T-cell lymphoma with iatrogenic immunosuppression and breast implants with an indolent variant of anaplastic large cell lymphoma. Epstein-Barr virus (EBV)-positive T-cell lymphomas rarely occur in the acquired immunodeficiency setting. Systemic T- and NK-cell lymphoma of childhood overlaps with chronic active EBV and reversible hemophagocytic lymphohistiocytosis-related T-cell lymphoproliferations.Immunodeficiencies predispose to T-cell hyperplasias, which must not be overdiagnosed as lymphoma. Many T-cell lymphomas in the immunodeficiency setting are likely coincidental, with specific exceptions. Systemic T- or NK-cell lymphomas are part of a spectrum of EBV+ T or NK lymphoproliferations and can present in the acquired immunodeficiency setting.
View details for DOI 10.1093/ajcp/aqw213
View details for Web of Science ID 000397108600005
View details for PubMedID 28395105
Primary/Congenital Immunodeficiency 2015 SH/EAHP Workshop Report-Part 5
AMERICAN JOURNAL OF CLINICAL PATHOLOGY
2017; 147 (2): 204-216
The 2015 Workshop of the Society for Hematopathology/European Association for Haematopathology aimed to review primary immunodeficiency and related lymphoproliferations.Primary immunodeficiencies were divided into immune dysregulation, DNA repair defects, low immunoglobulins, and combined immunodeficiencies.Autoimmune lymphoproliferative syndrome (ALPS) is a prototypical immune dysregulation-type immunodeficiency, with defects in T-cell signaling or apoptosis, expansion of T-cell subsets, and predisposition to hemophagocytic lymphohistiocytosis. DNA repair defects directly predispose to malignancy. Low immunoglobulin immunodeficiencies such as common variable immunodeficiency (CVID) have underlying T-cell repertoire abnormalities predisposing to autoimmunity and B-cell lymphoproliferations. The full spectrum of B-cell lymphoproliferative disorders occurs in primary immunodeficiency.Lymphoproliferations in primary immunodeficiency mirror those in other immunodeficiency settings, with monomorphic B- and sometimes T lymphoproliferative disorders enriched in DNA repair defects. Distinctive T-cell subset expansions in ALPS, CVID, and related entities can mimic lymphoma, and recognition of double-negative T-cell or cytotoxic T-cell expansions is key to avoid overdiagnosis.
View details for DOI 10.1093/ajcp/aqw215
View details for Web of Science ID 000397108600006
View details for PubMedID 28395106
- Immunodeficiency and Dysregulation: Report of the 2015 Workshop of the Society for Hematopathology/European Association for Haematopathology. American journal of clinical pathology 2017; 147 (2): 124–28
Normative data for flow cytometry immunophenotyping of benign lymph nodes sampled by surgical biopsy.
Journal of clinical pathology
To create clinically relevant normative flow cytometry data for understudied benign lymph nodes and characterise outliers.Clinical, histological and flow cytometry data were collected and distributions summarised for 380 benign lymph node excisional biopsies. Outliers for kappa:lambda light chain ratio, CD10:CD19 coexpression, CD5:CD19 coexpression, CD4:CD8 ratios and CD7 loss were summarised for histological pattern, concomitant diseases and follow-up course.We generated the largest data set of benign lymph node immunophenotypes by an order of magnitude. B and T cell antigen outliers often had background immunosuppression or inflammatory disease but did not subsequently develop lymphoma.Diagnostic immunophenotyping data from benign lymph nodes provide normative ranges for clinical use. Outliers raising suspicion for B or T cell lymphoma are not infrequent (26% of benign lymph nodes). Caution is indicated when interpreting outliers in the absence of excisional biopsy or clinical history, particularly in patients with concomitant immunosuppression or inflammatory disease.
View details for DOI 10.1136/jclinpath-2017-204687
View details for PubMedID 28916595
The Recent Pathology Residency Graduate Job Search Experience: A Synthesis of 5 Years of College of American Pathologists Job Market Surveys.
Archives of pathology & laboratory medicine
- Pathology residents and fellows tailor their training and job search strategies to an actively evolving specialty in the setting of scientific and technical advances and simultaneous changes in health care economics.- To assess the experience and outcome of the job search process of pathologists searching for their first non-fellowship position.- The College of American Pathologists (CAP) Graduate Medical Education Committee has during the past 5 years sent an annual job search survey each June to CAP junior members and fellows in practice 3 years or less who have actively searched for a non-fellowship position.- Job market indicators including job interviews, job offers, positions accepted, and job satisfaction have remained stable during the 5 years of the survey. Most survey respondents who had applied for at least 1 position had accepted a position at the time of the survey, and most applicants who had accepted a position were satisfied or very satisfied. However, most attested that finding a non-fellowship position was difficult. Despite a perceived push toward subspecialization in surgical pathology, the reported number of fellowships completed was stable. Respondent demographics were not associated with job search success with 1 significant exception: international medical school graduate respondents reported greater perceived difficulty in finding a position, and indeed, fewer reported having accepted a position.- Pathology residents and fellows seeking their first position have faced a relatively stable job market during the last 5 years, with most accepting positions with which they were satisfied.
View details for DOI 10.5858/arpa.2017-0207-CP
View details for PubMedID 29210592
A replicable CD271+ mesenchymal stromal cell density score: bringing the dysfunctional myelodysplastic syndrome niche to the diagnostic laboratory.
Leukemia & lymphoma
View details for PubMedID 27808583
Myelodysplastic syndrome macrophages have aberrant iron storage and heme oxygenase-1 expression.
Leukemia & lymphoma
2016; 57 (8): 1893-1902
Iron overload and transfusion dependance portend poor risk in myelodysplastic syndromes (MDS); bone marrow macrophages store iron and limit oxidative damage through heme oxygenase-1 (HO1). We assessed iron stores and macrophage HO1 expression in MDS using image analysis of intact diagnostic bone marrow biopsies and qualitative scoring of marrow aspirate iron among 129 cytopenic patients, 67 with MDS and 62 similarly aged patients with benign cytopenias. Using double immunofluorescence and sequential iron and immunohistochemistry staining, we showed that marrow iron colocalizes with HO1 and H-ferritin to CD163 + macrophages. Marrow iron was elevated in MDS independent of transfusion status, a finding of potential utility in distinguishing benign cytopenia from MDS. Among MDS patients only, CD163 + macrophage density and HO1 and H-ferritin expression by CD163 + macrophages increased in tandem with marrow iron. High HO1 was significantly associated with shorter overall survival among MDS patients independent of IPSSR and history of transfusion.
View details for DOI 10.3109/10428194.2015.1121259
View details for PubMedID 26758041
A humanized bone marrow ossicle xenotransplantation model enables improved engraftment of healthy and leukemic human hematopoietic cells
2016; 22 (7): 812-821
Xenotransplantation models represent powerful tools for the investigation of healthy and malignant human hematopoiesis. However, current models do not fully mimic the components of the human bone marrow (BM) microenvironment, and they enable only limited engraftment of samples from some human malignancies. Here we show that a xenotransplantation model bearing subcutaneous humanized ossicles with an accessible BM microenvironment, formed by in situ differentiation of human BM-derived mesenchymal stromal cells, enables the robust engraftment of healthy human hematopoietic stem and progenitor cells, as well as primary acute myeloid leukemia (AML) samples, at levels much greater than those in unmanipulated mice. Direct intraossicle transplantation accelerated engraftment and resulted in the detection of substantially higher leukemia-initiating cell (LIC) frequencies. We also observed robust engraftment of acute promyelocytic leukemia (APL) and myelofibrosis (MF) samples, and identified LICs in these malignancies. This humanized ossicle xenotransplantation approach provides a system for modeling a wide variety of human hematological diseases.
View details for DOI 10.1038/nm.4103
View details for Web of Science ID 000379366900021
View details for PubMedID 27213817
Beyond the Niche: Myelodysplastic Syndrome Topobiology in the Laboratory and in the Clinic
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
2016; 17 (4)
We review the murine and human microenvironment and hematopoietic stem cell niche in the context of intact bone marrow architecture in man and mouse, both in normal and in myelodysplastic syndrome marrow. We propose that the complexity of the hematopoietic stem cell niche can usefully be approached in the context of its topobiology, and we provide a model that incorporates in vitro and in vivo models as well as in situ findings from intact human marrow to explain the changes seen in myelodysplastic syndrome patients. We highlight the clinical application of the study of the bone marrow microenvironment and its topobiology in myelodysplastic syndromes.
View details for DOI 10.3390/ijms17040553
View details for Web of Science ID 000374585300132
View details for PubMedID 27089321
Alkylator-Induced and Patient-Derived Xenograft Mouse Models of Therapy-Related Myeloid Neoplasms Model Clinical Disease and Suggest the Presence of Multiple Cell Subpopulations with Leukemia Stem Cell Activity.
2016; 11 (7)
Acute myeloid leukemia (AML) is a heterogeneous group of aggressive bone marrow cancers arising from transformed hematopoietic stem and progenitor cells (HSPC). Therapy-related AML and MDS (t-AML/MDS) comprise a subset of AML cases occurring after exposure to alkylating chemotherapy and/or radiation and are associated with a very poor prognosis. Less is known about the pathogenesis and disease-initiating/leukemia stem cell (LSC) subpopulations of t-AML/MDS compared to their de novo counterparts. Here, we report the development of mouse models of t-AML/MDS. First, we modeled alkylator-induced t-AML/MDS by exposing wild type adult mice to N-ethyl-N-nitrosurea (ENU), resulting in several models of AML and MDS that have clinical and pathologic characteristics consistent with human t-AML/MDS including cytopenia, myelodysplasia, and shortened overall survival. These models were limited by their inability to transplant clinically aggressive disease. Second, we established three patient-derived xenograft models of human t-AML. These models led to rapidly fatal disease in recipient immunodeficient xenografted mice. LSC activity was identified in multiple HSPC subpopulations suggesting there is no canonical LSC immunophenotype in human t-AML. Overall, we report several new t-AML/MDS mouse models that could potentially be used to further define disease pathogenesis and test novel therapeutics.
View details for DOI 10.1371/journal.pone.0159189
View details for PubMedID 27428079
View details for PubMedCentralID PMC4948781
- Selective quantitation of microvessel density reveals sinusoidal expansion in myelodysplastic syndromes. Leukemia & lymphoma 2016: 1–4
Distinctive contact between CD34+ hematopoietic progenitors and CXCL12+ CD271+ mesenchymal stromal cells in benign and myelodysplastic bone marrow
2012; 92 (9): 1330-1341
Mesenchymal stromal cells (MSCs) support hematopoiesis and are cytogenetically and functionally abnormal in myelodysplastic syndrome (MDS), implying a possible pathophysiologic role in MDS and potential utility as a diagnostic or risk-stratifying tool. We have analyzed putative MSC markers and their relationship to CD34+ hematopoietic stem/progenitor cells (HSPCs) within intact human bone marrow in paraffin-embedded bone marrow core biopsies of benign, MDS and leukemic (AML) marrows using tissue microarrays to facilitate scanning, image analysis and quantitation. We found that CD271+, ALP+ MSCs formed an extensive branching perivascular, periosteal and parenchymal network. Nestin was brightly positive in capillary/arteriolar endothelium and occasional subendothelial cells, whereas CD146 was most brightly expressed in SMA+ vascular smooth muscle/pericytes. CD271+ MSCs were distinct by double immunofluorescence from CD163+ macrophages and were in close contact with but distinct from brightly nestin+ and from brightly CD146+ vascular elements. Double immunofluorescence revealed an intimate spatial relationship between CD34+ HSPCs and CD271+ MSCs; remarkably, 86% of CD34+ HSPCs were in direct contact with CD271+ MSCs across benign, MDS and AML marrows, predominantly in a perivascular distribution. Expression of the intercrine chemokine CXCL12 was strong in the vasculature in both benign and neoplastic marrow, but was also present in extravascular parenchymal cells, particularly in MDS specimens. We identified these parenchymal cells as MSCs by ALP/CXCL12 and CD271/CXCL12 double immunofluorescence. The area covered by CXCL12+ ALP+ MSCs was significantly greater in MDS compared with benign and AML marrow (P=0.021, Kruskal-Wallis test). The preservation of direct CD271+ MSC/CD34+ HSPC contact across benign and neoplastic marrow suggests a physiologically important role for the CD271+ MSC/CD34+ HSPC relationship and possible abnormal exposure of CD34+ HSPCs to increased MSC CXCL12 expression in MDS.
View details for DOI 10.1038/labinvest.2012.93
View details for Web of Science ID 000308274600008
View details for PubMedID 22710983
Entrustable Professional Activities for Pathology: Recommendations From the College of American Pathologists Graduate Medical Education Committee.
; 4: 2374289517714283
Competency-based medical education has evolved over the past decades to include the Accreditation Council for Graduate Medical Education Accreditation System of resident evaluation based on the Milestones project. Entrustable professional activities represent another means to determine learner proficiency and evaluate educational outcomes in the workplace and training environment. The objective of this project was to develop entrustable professional activities for pathology graduate medical education encompassing primary anatomic and clinical pathology residency training. The Graduate Medical Education Committee of the College of American Pathologists met over the course of 2 years to identify and define entrustable professional activities for pathology graduate medical education. Nineteen entrustable professional activities were developed, including 7 for anatomic pathology, 4 for clinical pathology, and 8 that apply to both disciplines with 5 of these concerning laboratory management. The content defined for each entrustable professional activity includes the entrustable professional activity title, a description of the knowledge and skills required for competent performance, mapping to relevant Accreditation Council for Graduate Medical Education Milestone subcompetencies, and general assessment methods. Many critical activities that define the practice of pathology fit well within the entrustable professional activity model. The entrustable professional activities outlined by the Graduate Medical Education Committee are meant to provide an initial framework for the development of entrustable professional activity-related assessment and curricular tools for pathology residency training.
View details for DOI 10.1177/2374289517714283
View details for PubMedID 28725792
View details for PubMedCentralID PMC5496684
Prospective Analysis of EBV plus PTLD Incidence in Pediatric Transplant Recipients in the Modern Era.
WILEY. 2018: 352–53
View details for Web of Science ID 000431965401270
Comparison of MYC Fluorescent In Situ Hybridization Testing of Diffuse Large B-cell Lymphomas in Fine Needle Aspiration and Surgical Specimens
NATURE PUBLISHING GROUP. 2018: 162
View details for Web of Science ID 000429308601095
Nodular Lymphocyte Predominant Hodgkin Lymphoma: Cytopathologic and Immunophenotypic Correlation and Diagnostic Pitfalls
NATURE PUBLISHING GROUP. 2018: 146
View details for Web of Science ID 000429308601051
Nodal Involvement by CD30+ Cutaneous Lymphoproliferative Disorders and Its Challenging Differentiation From Classical Hodgkin Lymphoma.
Archives of pathology & laboratory medicine
2018; 142 (1): 139–42
Primary cutaneous lymphomas are defined as non-Hodgkin lymphomas that present in the skin with no evidence of extracutaneous disease at the time of diagnosis. Mycosis fungoides is the most common type of primary cutaneous T-cell lymphoma, representing almost 50% of primary cutaneous T-cell lymphomas, and primary cutaneous CD30+ T-cell lymphoproliferative disorders are the second most common group (30%). Transformed mycosis fungoides is usually CD30+ and can involve multiple nodal sites; other primary cutaneous CD30+ T-cell lymphoproliferative disorders can also involve draining regional nodes. Nodal involvement by CD30+ T-cell lymphoproliferative disorders can mimic classical Hodgkin lymphoma, which can aberrantly express T-cell antigens. The aim of this article is to briefly review salient clinical, histologic, immunophenotypic, and molecular features that can be used to distinguish lymph node involvement by CD30+ cutaneous T-cell lymphomas and lymphoproliferative disorders from classical Hodgkin lymphoma, a clinically important differential diagnosis that represents a challenging task for the pathologist.
View details for DOI 10.5858/arpa.2016-0352-RS
View details for PubMedID 29257929
Tumor Formation of Adult Stem Cell Transplants in Rodent Arthritic Joints.
Molecular imaging and biology : MIB : the official publication of the Academy of Molecular Imaging
While imaging matrix-associated stem cell transplants aimed for cartilage repair in a rodent arthritis model, we noticed that some transplants formed locally destructive tumors. The purpose of this study was to determine the cause for this tumor formation in order to avoid this complication for future transplants.Adipose-derived stem cells (ADSC) isolated from subcutaneous adipose tissue were implanted into 24 osteochondral defects of the distal femur in ten athymic rats and two immunocompetent control rats. All transplants underwent serial magnetic resonance imaging (MRI) up to 6 weeks post-transplantation to monitor joint defect repair. Nine transplants showed an increasing size over time that caused local bone destruction (group 1), while 11 transplants in athymic rats (group 2) and 4 transplants in immunocompetent rats did not. We compared the ADSC implant size and growth rate on MR images, macroscopic features, histopathologic features, surface markers, and karyotypes of these presumed neoplastic transplants with non-neoplastic ADSC transplants.Implants in group 1 showed a significantly increased two-dimensional area at week 2 (p = 0.0092), 4 (p = 0.003), and 6 (p = 0.0205) compared to week 0, as determined by MRI. Histopathological correlations confirmed neoplastic features in group 1 with significantly increased size, cellularity, mitoses, and cytological atypia compared to group 2. Six transplants in group 1 were identified as malignant chondrosarcomas and three transplants as fibromyxoid sarcomas. Transplants in group 2 and immunocompetent controls exhibited normal cartilage features. Both groups showed a normal ADSC phenotype; however, neoplastic ADSC demonstrated a mixed population of diploid and tetraploid cells without genetic imbalance.ADSC transplants can form tumors in vivo. Preventive actions to avoid in vivo tumor formations may include karyotyping of culture-expanded ADSC before transplantation. In addition, serial imaging of ADSC transplants in vivo may enable early detection of abnormally proliferating cell transplants.
View details for DOI 10.1007/s11307-018-1218-7
View details for PubMedID 29869062
Magnetic Resonance Imaging of Tumor Associated Macrophages: Clinical Translation.
Clinical cancer research : an official journal of the American Association for Cancer Research
Tumor associated macrophages (TAM) in malignant tumors have been linked to tumor aggressiveness and represent a new target for cancer immunotherapy. As new TAM-targeted immunotherapies are entering clinical trials, it is important to detect and quantify TAM with non-invasive imaging techniques. The purpose of this study was to determine if ferumoxytol-enhanced MRI can detect TAM in lymphomas and bone sarcomas of pediatric patients and young adults.In a first-in-patient, IRB-approved prospective clinical trial, 25 pediatric and young adult patients with lymphoma or bone sarcoma underwent ferumoxytol-enhanced MRI. To confirm ferumoxytol enhancement, five pilot patients (2 lymphoma, 3 bone sarcoma) underwent pre- and post-contrast MRI. Subsequently, 20 patients (10 lymphoma, 10 bone sarcoma) underwent ferumoxytol-enhanced MRI 24-48 hours after intravenous injection, followed by tumor biopsy/resection and macrophage staining. To determine if ferumoxytol-MRI can differentiate tumors with different TAM content, we compared T2* relaxation times of lymphomas and bone sarcomas. Tumor T2* values of 20 patients were correlated with CD68+ and CD163+ TAM quantities on histopathology.Significant ferumoxytol tumor enhancement was noted on post-contrast scans compared to pre-contrast scans (P = 0.036). Bone sarcomas and lymphomas demonstrated significantly different MRI enhancement and TAM density (P < 0.05). Within each tumor group, T2* signal enhancement on MR images correlated significantly with the density of CD68+ and CD163+ TAM (P < 0.05).Ferumoxytol-enhanced MRI is immediately clinically applicable and could be used to stratify patients with TAM-rich tumors to immune-targeted therapies and to monitor tumor response to these therapies.
View details for DOI 10.1158/1078-0432.CCR-18-0673
View details for PubMedID 29764855
Bone marrow histomorphologic criteria can accurately diagnose hemophagocytic lymphohistiocytosis.
Hemophagocytic lymphohistiocytosis is a rare multi-system inflammatory disorder with diagnostic criteria based on the HLH-2004 trial. Hemophagocytosis is the only histomorphologic criterion, but in isolation is neither specific nor sensitive for the diagnosis of hemophagocytic lymphohistiocytosis. While objective thresholds for clinical and laboratory criteria have been established, specific criteria for histomorphologic evidence of hemophagocytosis in hemophagocytic lymphohistiocytosis have not been rigorously evaluated or established. We sought to determine if numerical and objective criteria for morphologic hemophagocytosis could be identified, and if such criteria would aid in the diagnosis of hemophagocytic lymphohistiocytosis. We analyzed the morphologic features of hemophagocytosis in 78 patients presenting with clinical features suspicious for hemophagocytic lymphohistiocytosis: 40 patients with hemophagocytic lymphohistiocytosis and 38 patients without hemophagocytic lymphohistiocytosis. We demonstrate that non-nucleated erythrophagocytosis alone is a non-specific finding, while hemophagocytosis of granulocytes (1 per 1000 cells, area under the curve: 0.92, 95% confidence interval: 0.86, 0.99), nucleated erythrocytes (4 per 1000 cells, area under the curve: 0.92, 95% confidence interval: 0.87, 0.98), and at least one hemophagocyte containing multiple nucleated cells (area under the curve: 0.91, 95% confidence interval: 0.85, 0.95) are strongly associated with hemophagocytic lymphohistiocytosis. Joint modeling of hemophagocytes containing engulfed granulocytes, nucleated erythrocytes, and lymphocytes effectively distinguished between hemophagocytic lymphohistiocytosis and non-hemophagocytic lymphohistiocytosis (cross-validated area under curve: 0.90, 95% confidence interval: 0.83, 0.97).
View details for DOI 10.3324/haematol.2017.186627
View details for PubMedID 29903767
- KB004, a first in class monoclonal antibody targeting the receptor tyrosine kinase EphA3, in patients with advanced hematologic malignancies: Results from a phase 1 study (vol 50, pg 123, 2016) LEUKEMIA RESEARCH 2017; 59: 65
B-Cell and Classical Hodgkin Lymphomas Associated With Immunodeficiency 2015 SH/EAHP Workshop Report-Part 2
AMERICAN JOURNAL OF CLINICAL PATHOLOGY
2017; 147 (2): 153-170
The 2015 Workshop of the Society for Hematopathology/European Association for Haematopathology submitted small and large B-cell lymphomas (BCLs), including classical Hodgkin lymphoma (CHL), in the context of immunodeficiency.Clinicopathologic and molecular features were studied to explore unifying concepts in malignant B-cell proliferations across immunodeficiency settings.Cases submitted to the workshop spanned small BCLs presenting as nodal or extranodal marginal zone lymphoma and lymphoplasmacytic lymphoma, Epstein-Barr virus (EBV) positive in 75% of cases. Submitted large BCLs formed a spectrum from diffuse large B-cell lymphoma (DLBCL) to CHL across immunodeficiency settings. Additional studies demonstrated overexpression of PD-L1 and molecular 9p24 alterations in the large BCL spectrum and across different immunodeficiency settings.Small BCLs occur in all immunodeficiency settings, and EBV positivity is essential for their recognition as immunodeficiency related. Large BCLs include a spectrum from DLBCL to CHL across all immunodeficiency settings; immunohistochemical and molecular features are suggestive of shared pathogenetic mechanisms involving PD-L1 immune checkpoints.
View details for DOI 10.1093/ajcp/aqw216
View details for Web of Science ID 000397108600003
View details for PubMedID 28395108
EBV-Positive B-Cell Proliferations of Varied Malignant Potential 2015 SH/EAHP Workshop Report-Part 1
AMERICAN JOURNAL OF CLINICAL PATHOLOGY
2017; 147 (2): 129-152
The 2015 Workshop of the Society for Hematopathology/European Association for Haematopathology aimed to review B-cell proliferations of varied malignant potential associated with immunodeficiency.The Workshop Panel reviewed all cases of B-cell hyperplasias, polymorphic B-lymphoproliferative disorders, Epstein-Barr virus (EBV)-positive mucocutaneous ulcer, and large B-cell proliferations associated with chronic inflammation and rendered consensus diagnoses. Disease definitions, boundaries with more aggressive B-cell proliferations, and association with EBV were explored.B-cell proliferations of varied malignant potential occurred in all immunodeficiency backgrounds. Presentation early in the course of immunodeficiency and in younger age groups and regression with reduction of immunosuppression were characteristic features. EBV positivity was essential for diagnosis in some hyperplasias where other specific defining features were absent.This spectrum of B-cell proliferations show similarities across immunodeficiency backgrounds. Localized forms of immunodeficiency disorders arise in immunocompetent patients most likely due to chronic immune stimulation and, despite aggressive histologic features, often show indolent clinical behavior.
View details for DOI 10.1093/ajcp/aqw214
View details for Web of Science ID 000397108600002
View details for PubMedID 28395107
HHV8/KSHV-Positive Lymphoproliferative Disorders and the Spectrum of Plasmablastic and Plasma Cell Neoplasms 2015 SH/EAHP Workshop Report-Part 3
AMERICAN JOURNAL OF CLINICAL PATHOLOGY
2017; 147 (2): 171-187
The 2015 Workshop of the Society for Hematopathology/European Association for Haematopathology aimed to review immunodeficiency-related lymphoproliferative disorders with plasmablastic and plasma cell differentiation.The workshop panel reviewed human herpes virus 8 (HHV8)/Kaposi sarcoma herpesvirus (KSHV)-associated lesions and other lesions exhibiting plasma cell differentiation, including plasmablastic proliferations with features of myeloma/plasmacytoma, plasmablastic neoplasms presenting in extranodal sites and effusion-based lymphomas, and rendered a consensus diagnosis.The spectrum of HHV8/KSHV-associated proliferations ranged from multicentric Castleman disease (MCD) to MCD with plasmablastic aggregates to HHV8+ diffuse large B-cell lymphoma and germinotrophic lymphoproliferative disorder. Comparisons across effusion-based lymphomas with and without HHV8/KSHV and plasmablastic lymphomas in immunodeficient and immunocompetent patients were discussed.The presence or absence of HHV8/KSHV is a defining feature in disorders associated with Castleman disease, although their differential diagnosis and recognition of progression may be challenging. Plasmablastic proliferations overlap with myeloma/plasmacytoma as well as extranodal and effusion-based lymphomas. The involvement of Epstein-Barr virus is typically variable.
View details for DOI 10.1093/ajcp/aqw218
View details for Web of Science ID 000397108600004
View details for PubMedID 28395104
Perceptions of Unprofessional Attitudes and Behaviors: Implications for Faculty Role Modeling and Teaching Professionalism During Pathology Residency.
Archives of pathology & laboratory medicine
- Changes occurring in medicine have raised issues about medical professionalism. Professionalism is included in the Core Competencies and Milestones for all pathology residents. Previous studies have looked at resident professionalism attitudes and behaviors in primary care but none have looked specifically at pathology.- To examine behavior and attitudes toward professionalism within pathology and to determine how professionalism is taught in residency programs.- Surveys were sent to all College of American Pathologists junior members and all pathology residency program directors, and responses were compared.- Although no single behavior received the same professionalism rating among residents and program directors, both groups identified the same behaviors as being the most unprofessional: posting identifiable patient information or case images to social media, making a disparaging comment about a physician colleague or member of the support staff on social media or in a public space, and missing work without reporting the time off. Faculty were observed displaying most of these behaviors as often or more often than residents by both groups. The most common means to teach professionalism in pathology residencies is providing feedback as situations arise and teaching by example. Age differences were found within each group and between groups for observed behaviors and attitudes.- As teaching by example was identified as a common educational method, faculty must be aware of the role their behavior and attitudes have in shaping resident behavior and attitudes. These results suggest a need for additional resources to teach professionalism during pathology residency.
View details for DOI 10.5858/arpa.2016-0477-CP
View details for PubMedID 28686498
Clinical Impact of the 2016 Update to the WHO Lymphoma Classification.
Current treatment options in oncology
2017; 18 (7): 45
The 2016 revision of the WHO classification of lymphoid neoplasms includes new entities along with a clearer definition of provisional and definitive subtypes based on better understanding of the molecular drivers of lymphomas. These changes impact current treatment paradigms and provide a framework for future clinical trials. Additionally, this update recognizes several premalignant or predominantly indolent entities and underscores the importance of avoiding unnecessarily aggressive treatment in the latter subsets.
View details for DOI 10.1007/s11864-017-0483-z
View details for PubMedID 28670664
KB004, a first in class monoclonal antibody targeting the receptor tyrosine kinase EphA3, in patients with advanced hematologic malignancies: Results from a phase 1 study.
2016; 50: 123-131
EphA3 is an Ephrin receptor tyrosine kinase that is overexpressed in most hematologic malignancies. We performed a first-in-human multicenter phase I study of the anti-EphA3 monoclonal antibody KB004 in refractory hematologic malignancies in order to determine safety and tolerability, along with the secondary objectives of pharmacokinetics (PK) and pharmacodynamics (PD) assessments, as well as preliminary assessment of efficacy. Patients were enrolled on a dose escalation phase (DEP) initially, followed by a cohort expansion phase (CEP). KB004 was administered by intravenous infusion on days 1, 8, and 15 of each 21-day cycle in escalating doses. A total of 50 patients (AML 39, MDS/MPN 3, MDS 4, DLBCL 1, MF 3) received KB004 in the DEP; an additional 14 patients were treated on the CEP (AML 8, MDS 6). The most common toxicities were transient grade 1 and grade 2 infusion reactions (IRs) in 79% of patients. IRs were dose limiting above 250mg. Sustained exposure exceeding the predicted effective concentration (1ug/mL) and covering the 7-day interval between doses was achieved above 190mg. Responses were observed in patients with AML, MF, MDS/MPN and MDS. In this study, KB004 was well tolerated and clinically active when given as a weekly infusion.
View details for DOI 10.1016/j.leukres.2016.09.012
View details for PubMedID 27736729
Two cases of histiocytic sarcoma with BCL2 translocations and occult or subsequent follicular lymphoma.
2016; 55: 39-43
Histiocytic sarcoma is rare and difficult to distinguish from histologic mimics such as myeloid sarcoma due to its relatively nonspecific immunoprofile. A subset of histiocytic sarcomas are clonally related to synchronous or metachronous follicular lymphomas. Interestingly, the histiocytic tumor component has been shown to harbor BCL2 gene translocations that are identical to those found in the lymphoma. We present one case of histiocytic sarcoma and initially occult follicular lymphoma in which detection of a BCL2 gene translocation helped support the diagnosis. We also provide follow up regarding a previously published case of histiocytic sarcoma with IGH/BCL2 fusion gene in which the patient subsequently developed follicular lymphoma and, later, diffuse large B-cell lymphoma. Our findings suggest that BCL2 gene translocations are a recurrent feature of a distinct subset of histiocytic sarcomas that are associated with follicular lymphoma; the follicular lymphoma component may be clinically occult at the time of diagnosis. Testing for an IGH/BCL2 translocation should be considered in the diagnostic workup of difficult to characterize neoplasms with histiocytic/monocytic morphology and immunoprofile.
View details for DOI 10.1016/j.humpath.2016.04.004
View details for PubMedID 27134111
Pediatric-type nodal follicular lymphoma: a biologically distinct lymphoma with frequent MAPK pathway mutations.
2016; 128 (8): 1093-1100
Pediatric-type nodal follicular lymphoma (PTNFL) is a variant of follicular lymphoma (FL) characterized by limited-stage presentation and invariably benign behavior despite often high-grade histological appearance. It is important to distinguish PTNFL from typical FL in order to avoid unnecessary treatment; however, this distinction relies solely on clinical and pathological criteria, which may be variably applied. To define the genetic landscape of PTNFL, we performed copy-number analysis, exome and/or targeted sequencing of 26 PTNFLs (16 pediatric, 10 adult). The most commonly mutated gene in PTNFL was MAP2K1, encoding MEK1, with a mutation frequency of 43%. All MAP2K1 mutations were activating missense mutations localized to exons 2 and 3, which encode negative regulatory and catalytic domains, respectively. Missense mutations in MAPK1 (2/22), and RRAS (1/22) were identified in cases that lacked MAP2K1 mutations. The second most commonly mutated gene in PTNFL was TNFRSF14, with a mutation frequency of 29%, similar to that seen in limited-stage typical FL (p=0.35). PTNFL was otherwise genomically bland, and specifically lacked recurrent mutations in epigenetic modifiers (e.g. CREBBP, KMT2D). Copy number aberrations (CNAs) affected a mean of only 0.5% of PTNFL genomes, compared to 10% of limited-stage typical FL genomes (p<0.02). Importantly, the mutational profiles of PTNFLs in children and adults were highly similar. Together, these findings define PTNFL as a biologically and clinically distinct indolent lymphoma of children and adults characterized by a high prevalence of MAP kinase pathway mutations and a near absence of mutations in epigenetic modifiers.
View details for DOI 10.1182/blood-2015-12-682591
View details for PubMedID 27325104
- Mucocutaneous ulcer: a mimic of EBV?+?diffuse large B cell lymphoma in the immunodeficiency setting. Leukemia & lymphoma 2016; 57 (8): 1982-1983
Pathophysiological significance and therapeutic targeting of germinal center kinase in diffuse large B-cell lymphoma.
2016; 128 (2): 239-248
Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma (NHL), yet 40-50% of patients will eventually succumb to their disease demonstrating a pressing need for novel therapeutic options. Gene expression profiling has identified messenger RNA's that lead to transformation, but critical events transforming cells are normally executed by kinases. Therefore, we hypothesized that previously unrecognized kinases may contribute to DLBCL pathogenesis. We performed the first comprehensive analysis of global kinase activity in DLBCL, to identify novel therapeutic targets, and discovered that Germinal Center Kinase (GCK) was extensively activated. GCK RNA interference and small molecule inhibition induced cell cycle arrest and apoptosis in DLBCL cell lines and primary tumors in vitro and decreased the tumor growth rate in vivo, resulting in a significantly extended lifespan of mice bearing DLBCL xenografts. GCK expression was also linked to adverse clinical outcome in a cohort of 151 primary DLBCL patients. These studies demonstrate, for the first time, that GCK is a molecular therapeutic target in DLBCL tumors and that inhibiting GCK may significantly extend DLBCL patient survival. Since the majority of DLBCL tumors (~80%) exhibit activation of GCK, this therapy may be applicable to most patients.
View details for DOI 10.1182/blood-2016-02-696856
View details for PubMedID 27151888
- Plasmacytic posttransplant lymphoproliferative disorder with hyperviscosity syndrome in a child after liver transplant. Hepatology 2016
Pure Erythroid Leukemia and Erythroblastic Sarcoma Evolving From Chronic Myeloid Neoplasms
AMERICAN JOURNAL OF CLINICAL PATHOLOGY
2016; 145 (4): 538-551
Pure erythroid leukemia (PEL) is an extremely rare entity that may, even more rarely, evolve from a preexisting chronic myeloid neoplasm (CMN); there is minimal literature regarding this latter phenomenon.We describe 14 patients with PEL that represented progression from a preexisting myelodysplastic syndrome (MDS, n = 8) or myeloproliferative neoplasm (MPN, n = 6), three of which manifested as erythroblastic sarcoma (EBS), a rare entity. These patients had a highly complex karyotype with prominent clonal evolution and a very aggressive clinical course.Patients with PEL from MDS showed a more rapid progression time to PEL and had lower platelet counts compared with PEL from MPN. No other significant differences were found between the two groups.These data represent the largest cohort of patients with PEL and an antecedent CMN, as well as the largest series of EBS reported to date, and underscore the unique morphologic, cytogenetic, immunophenotypic, and clinical features of this uncommon entity.
View details for DOI 10.1093/ajcp/aqw033
View details for Web of Science ID 000376947200012
View details for PubMedID 27124944
Isolated Follicles Enriched for Centroblasts and Lacking t(14;18)/BCL2 in Lymphoid Tissue: Diagnostic and Clinical Implications
2016; 11 (3)
We sought to address the significance of isolated follicles that exhibit atypical morphologic features that may be mistaken for lymphoma in a background of reactive lymphoid tissue. Seven cases that demonstrated centroblast-predominant isolated follicles and absent BCL2 staining in otherwise-normal lymph nodes were studied. Four of seven cases showed clonal B-cell proliferations amid a polyclonal B cell background; all cases lacked the IGH-BCL2 translocation and BCL2 protein expression. Although three patients had invasive breast carcinoma at other sites, none were associated with systemic lymphoma up to 44 months after diagnosis. The immunoarchitectural features of these highly unusual cases raise the question of whether a predominance of centroblasts and/or absence of BCL2 expression could represent a precursor lesion or atypical reactive phenomenon. Differentiating such cases from follicular lymphoma or another mimic is critical, lest patients with indolent proliferations be exposed to unnecessarily aggressive treatment.
View details for DOI 10.1371/journal.pone.0151735
View details for Web of Science ID 000372582800093
View details for PubMedCentralID PMC4798531
Professionalism in Pathology: A Case-Based Approach as a Potential Educational Tool.
Archives of pathology & laboratory medicine
-Professionalism issues in residency training can be difficult to assess and manage. Generational or role-based differences may also exist between faculty and residents as to what constitutes unprofessional behavior and how to manage it.-To examine and compare how faculty and residents would approach the same 5 case scenarios detailing various aspects of unprofessional behavior.-Five case scenarios highlighting various unprofessional behaviors were presented in a workshop at an annual meeting of pathology department chairs, residency program directors, and undergraduate pathology medical educators (ie, pathologists involved in medical student pathology education). The same cases were presented to a cohort of pathology residents currently in training. A standard set of responses were offered to the participants, polling results were collected electronically, and results were compared.-Faculty and residents were fairly consistent within their respective groups. In a subset of cases, faculty were more likely to favor working with the individual in the scenario, whereas resident respondents were more likely to favor either no response or a severe response. Generational or role-based differences were also potentially evident.-Assessing expectations and differences around professionalism for both faculty and residents should be considered as part of any educational and management approach for professionalism. Although a level of generational differences appears to be evident in this study regarding the recognition and management of unprofessional behavior, there was also agreement in some cases. Further exploration into the discrepant responses between faculty and residents may prove useful in developing educational, assessment, and remediation resources.
View details for DOI 10.5858/arpa.2016-0217-CP
View details for PubMedID 27763788
Dasatinib-related Follicular Hyperplasia: An Underrecognized Entity With Characteristic Morphology.
American journal of surgical pathology
2015; 39 (10): 1363-1369
Dasatinib, a second-generation tyrosine kinase inhibitor with activity against BCR-ABL1 and other Src family tyrosine kinases, is approved as a first-line treatment option for Philadelphia chromosome-positive chronic myelogenous leukemia (CML) in the chronic phase. Recently, lymphadenopathy with morphologic features of reactive follicular hyperplasia was described in a cohort of patients with CML on long-term dasatinib therapy. However, the complete morphologic and immunophenotypic features of this previously underappreciated adverse effect have not been fully described. Herein, we report 3 cases of unexplained lymphadenopathy resulting in multiple diagnostic procedures in patients with CML and a history of long-term dasatinib therapy. Morphologic examination demonstrated preserved nodal architecture showing hybrid features of progressive transformation of germinal centers and Castleman-type changes in a background of florid follicular hyperplasia. Large germinal centers were disrupted by complex infolding of IgD mantle zones arranged as cuffs surrounding perforating capillaries. Other abnormalities variably present included decreased CD20 expression among polytypic B cells and increased Epstein-Barr virus reactivity in scattered paracortical cells and/or individual germinal centers. B-cell clonality studies showed no predominant clonal rearrangements. Consideration of dasatinib-related lymphadenopathy may pre-empt unnecessary repeat diagnostic procedures in patients with CML or other dasatinib-susceptible malignancies and persistent lymphadenopathy.
View details for DOI 10.1097/PAS.0000000000000488
View details for PubMedID 26360368
Occult Dermal Lymphatic Involvement Is Frequent in Primary Cutaneous Anaplastic Large Cell Lymphoma.
American Journal of dermatopathology
2015; 37 (10): 767-770
Primary cutaneous anaplastic large cell lymphoma (pcALCL) is an indolent T-cell lymphoproliferative disorder managed with low-dose radiation therapy, surgery, and/or mild chemotherapy; patients with extensive limb disease (ELD) have a more aggressive clinical course. We have previously demonstrated that histologically apparent vascular involvement in pcALCL is lymphatic. We hypothesized that histologically occult lymphatic involvement may be associated with particular patterns of disease spread that could involve lymphangitic spread including locoregional spread of disease in the form of ELD and extracutaneous spread of disease. We have therefore set out to quantitate the incidence of occult lymphovascular involvement in pcALCL and to assess for an association between lymphovascular involvement and these patterns of disease. We performed immunohistochemistry for the lymphovascular marker D2-40 on skin biopsies from 29 patients with pcALCL followed in the Stanford Cutaneous Lymphoma Clinic. Immunohistochemically evident dermal lymphovascular involvement was found in nearly half of cases examined (48%; 95% confidence interval, 29%-67%). There was a nonsignificant trend toward a higher prevalence of ELD among patients with pcALCL involving dermal lymphatics (7% vs. 29%; p = 0.12). In this small cohort, there was no indication of a significantly more aggressive disease course in patients with lymphatic involvement either in the form of disease-related mortality (one each in the lymphatic and nonlymphatic groups) or in time to extracutaneous involvement.
View details for DOI 10.1097/DAD.0000000000000377
View details for PubMedID 26381026
Lymph node involvement by mycosis fungoides and Sezary syndrome mimicking angioimmunoblastic T-cell Lymphoma
2015; 46 (9): 1382-1389
Clinical management of cutaneous T-cell lymphoma (CTCL) and angioimmunoblastic T-cell lymphoma (AITL) differs markedly. Diagnostic distinction is critical. Herein, we describe a series of 4 patients with clinically, molecularly, and histopathologically annotated mycosis fungoides or Sézary syndrome whose nodal disease mimicked AITL. The patients otherwise exhibited classic clinical manifestations of mycosis fungoides/Sézary syndrome preceding the onset of lymphadenopathy by 1 to 5 years. Skin biopsies revealed epidermotropic infiltrates characteristic of CTCL. Lymph node biopsies revealed dense CD4+ T-cell infiltrates that coexpressed follicular helper T-cell markers and were accompanied by proliferations of high endothelial venules and arborizing CD21+ follicular dendritic cell networks. Two patients had T-cell receptor gene rearrangement studies performed on their skin, lymph node, and peripheral blood demonstrating identical polymerase chain reaction clones in all 3 tissues. A small secondary clonal B-cell population was present in 1 patient that mimicked the B-cell proliferations known to accompany AITL and persisted on successive nodal biopsies over several years. This latter phenomenon has not previously been described in CTCL. The potential for patients to be misdiagnosed with AITL for lack of consideration of advanced-stage CTCL with nodal involvement underscores the necessity of information sharing among the various pathologists and clinicians involved in the care of each patient.
View details for DOI 10.1016/j.humpath.2015.05.024
View details for Web of Science ID 000360779200017
- Genomic analysis of mycosis fungoides and Sezary syndrome identifies recurrent alterations in TNFR2 NATURE GENETICS 2015; 47 (9): 1056-?
- Mesenchymal Stromal Cell Density Is Increased in Higher Grade Myelodysplastic Syndromes and Independently Predicts Survival AMERICAN JOURNAL OF CLINICAL PATHOLOGY 2014; 142 (6): 795-802
Intralymphatic Cutaneous Anaplastic Large Cell Lymphoma/Lymphomatoid Papulosis: Expanding the Spectrum of CD30-positive Lymphoproliferative Disorders.
American journal of surgical pathology
2014; 38 (9): 1203-1211
Intravascular large B-cell lymphomas and EBV NK/T-cell lymphomas commonly follow an aggressive clinical course. We recently reported an entirely intravascular anaplastic large cell lymphoma (ALCL) in the skin with a surprisingly indolent clinical course; interestingly, this lymphoma involved the lymphatic rather than the blood vasculature. We hypothesized that intravascular skin-limited ALCL is distinct from aggressive systemic intravascular lymphomas in its intralymphatic localization and clinical course. We now describe 18 cases of cutaneous intravascular large cell lymphoproliferations from 4 institutions. All 12 intravascular large T-cell lesions were intralymphatic; the majority (9) were CD30 T-cell lymphoproliferative disorders (TLPDs), 5 further classified as intravascular ALK ALCL. One ALK ALCL and 2 benign microscopic intravascular T-cell proliferations were also intralymphatic. A single case of otherwise typical cutaneous follicle center lymphoma contained intralymphatic centroblasts. The clinical and pathologic characteristics of the CD30 TLPDs were similar to those of their extravascular counterparts, including extralymphatic dermal involvement in a subset, DUSP22-IRF4 translocations in half of tested ALK ALCLs, and associated mycosis fungoides in 1; most were skin-limited at baseline and remained so at relapse. All 5 cases of intravascular large B-cell lymphoma involved the blood vasculature and behaved in a clinically aggressive manner; the ALK ALCL, although intralymphatic, was systemic and clinically aggressive. We propose that cutaneous ALK ALCL and related CD30 ALK TLPDs involving the lymphatics are part of an expanding spectrum of CD30 TLPDs. The identification of intralymphatic as distinct from blood vascular localization may provide critical prognostic and therapeutic information.
View details for DOI 10.1097/PAS.0000000000000217
View details for PubMedID 24805854
- Vascular endothelial growth factor: the salt in the Hodgkin cytokine stew? Leukemia & lymphoma 2014; 55 (3): 474-475
Update on Myelodysplastic Syndromes Classification and Prognosis.
Surgical pathology clinics
2013; 6 (4): 693-728
Myelodysplastic syndromes (MDS) are a collection of cytogenetically heterogeneous clonal bone marrow (BM) failure disorders derived from aberrant hematopoietic stem cells in the setting of an aberrant hematopoietic stem cell niche. Patients suffer from variably progressive and symptomatic bone marrow failure with a risk of leukemic transformation. Diagnosis of MDS has long been based on morphologic assessment and blast percentage as in the original French-American-British classification. The recently developed Revised International Prognostic Scoring System provides improved prognostication using more refined cytogenetic, marrow blast, and cytopenia parameters. With the advent of deep sequencing technologies, dozens of molecular abnormalities have been identified in MDS.
View details for DOI 10.1016/j.path.2013.08.005
View details for PubMedID 26839194
Intravascular ALK-negative Anaplastic Large Cell Lymphoma With Localized Cutaneous Involvement and an Indolent Clinical Course Toward Recognition of a Distinct Clinicopathologic Entity
AMERICAN JOURNAL OF SURGICAL PATHOLOGY
2013; 37 (4): 617-623
Intravascular large T-cell or NK-cell lymphomas rarely present with cutaneous involvement. Intravascular cytotoxic T or NK lymphomas presenting in the skin (cIT/NKL) are often EBV, and reported cases follow a highly aggressive clinical course. Intravascular anaplastic large cell lymphoma (ALCL) by contrast is extraordinarily rare and, when it presents in the skin, raises the question of aggressive clinical behavior in the manner of cIT/NKL versus indolent clinical behavior in the manner of primary cutaneous ALCL. Here we describe a case of localized cutaneous intravascular anaplastic lymphoma kinase-negative ALCL (cIALCL) with a very indolent clinical course. The patient experienced a single cutaneous relapse and remains alive without disease 4 years after diagnosis. Review of the literature reveals multiple clinicopathologic differences between cIALCL and cIT/NKL: distribution (cIALCL, single skin region, P=0.021, Fisher exact test); histology (cIALCL, cohesive with necrosis, P=0.005); immunophenotype (cIALCL, strongly CD30, P=0.021; cIT/NKL, CD56 and/or EBV, P=0.003); and indolent clinical behavior with a trend toward better overall survival (P=0.067, Kaplan-Meier survival analysis). Our index case of cIALCL and 1 other tested case were immunohistochemically confirmed to be intralymphatic (contained within D2-40+vessels) as compared with the blood vessel localization of cIT/NKL. Recognition of cIALCLs as a distinct clinicopathologic entity, and in particular their distinction from aggressive, usually EBV cIT/NKLs, may be possible on the basis of a combination of clinicopathologic criteria, allowing for localized therapy in a subset of patients.
View details for DOI 10.1097/PAS.0b013e318280aa9c
View details for Web of Science ID 000316184000019
View details for PubMedID 23480896
IgG4-positive Sclerosing Orbital Inflammation Involving the Conjunctiva: A Case Report
OCULAR IMMUNOLOGY AND INFLAMMATION
2012; 20 (5): 375-377
To describe IgG4-positive sclerosing orbital inflammation with prominent conjunctival and scleral involvement.Case report.Clinical, radiologic, and pathologic correlation.A 66-year-old man presented with right eye redness and irritation. Examination revealed unilateral scleritis and nongranulomatous anterior uveitis with elevated p-ANCA and CRP. Orbital CT scan showed inferotemporal scleral thickening. Biopsy revealed sclerosis and IgG4-positive plasma cells in the conjunctiva and inferior rectus.IgG4-mediated sclerosing inflammation is well-recognized in the orbit and adnexa, particularly the lacrimal gland. Scleritis with anterior uveitis should be recognized as a possible presentation for this entity, which has important systemic associations.
View details for DOI 10.3109/09273948.2012.709574
View details for Web of Science ID 000309471900011
View details for PubMedID 23030356
- Histoplasmosis Presenting with Ulcers on the Soft Palate JOURNAL OF GENERAL INTERNAL MEDICINE 2012; 27 (9): 1219-1219
In situ vaccination against mycosis fungoides by intratumoral injection of a TLR9 agonist combined with radiation: a phase 1/2 study
2012; 119 (2): 355-363
We have developed and previously reported on a therapeutic vaccination strategy for indolent B-cell lymphoma that combines local radiation to enhance tumor immunogenicity with the injection into the tumor of a TLR9 agonist. As a result, antitumor CD8(+) T cells are induced, and systemic tumor regression was documented. Because the vaccination occurs in situ, there is no need to manufacture a vaccine product. We have now explored this strategy in a second disease: mycosis fungoides (MF). We treated 15 patients. Clinical responses were assessed at the distant, untreated sites as a measure of systemic antitumor activity. Five clinically meaningful responses were observed. The procedure was well tolerated and adverse effects consisted mostly of mild and transient injection site or flu-like symptoms. The immunized sites showed a significant reduction of CD25(+), Foxp3(+) T cells that could be either MF cells or tissue regulatory T cells and a similar reduction in S100(+), CD1a(+) dendritic cells. There was a trend toward greater reduction of CD25(+) T cells and skin dendritic cells in clinical responders versus nonresponders. Our in situ vaccination strategy is feasible also in MF and the clinical responses that occurred in a subset of patients warrant further study with modifications to augment these therapeutic effects. This study is registered at www.clinicaltrials.gov as NCT00226993.
View details for DOI 10.1182/blood-2011-05-355222
View details for Web of Science ID 000299268900012
View details for PubMedID 22045986
View details for PubMedCentralID PMC3257006
Increased CD271+CXCL12 Chemokine Overproducing Mesenchymal Stromal Cells Maintain Distinctive Association with CD34+Hematopoietic Progenitor/Stem Cells in Myelodysplastic Syndrome
53rd Annual Meeting and Exposition of the American-Society-of-Hematology (ASH)
AMER SOC HEMATOLOGY. 2011: 1202–
View details for Web of Science ID 000299597104140
In Situ Vaccination with TLR9 Agonist Combined with Local Radiation In Mycosis Fungoides: Analysis of Phase I/II Study
52nd Annual Meeting and Exposition of the American-Society-of-Hematology (ASH)
AMER SOC HEMATOLOGY. 2010: 130–30
View details for Web of Science ID 000289662200287
In Situ Tissue Microarray Cell-Lineage Specific Analysis of Protein Expression In Intact Myelodysplastic Bone Marrow: Data on Putative Poor Prognosis Biomarkers
52nd Annual Meeting and Exposition of the American-Society-of-Hematology (ASH)
AMER SOC HEMATOLOGY. 2010: 787–87
View details for Web of Science ID 000289662202111
CD81 protein is expressed at high levels in normal germinal center B cells and in subtypes of human lymphomas
2010; 41 (2): 271-280
CD81 is a tetraspanin cell surface protein that regulates CD19 expression in B lymphocytes and enables hepatitis C virus infection of human cells. Immunohistologic analysis in normal hematopoietic tissue showed strong staining for CD81 in normal germinal center B cells, a cell type in which its increased expression has not been previously recognized. High-dimensional flow cytometry analysis of normal hematopoietic tissue confirmed that among B- and T-cell subsets, germinal center B cells showed the highest level of CD81 expression. In more than 800 neoplastic tissue samples, its expression was also found in most non-Hodgkin lymphomas. Staining for CD81 was rarely seen in multiple myeloma, Hodgkin lymphoma, or myeloid leukemia. In hierarchical cluster analysis of diffuse large B-cell lymphoma, staining for CD81 was most similar to other germinal center B cell-associated markers, particularly LMO2. By flow cytometry, CD81 was expressed in diffuse large B-cell lymphoma cells independent of the presence or absence of CD10, another germinal center B-cell marker. The detection of CD81 in routine biopsy samples and its differential expression in lymphoma subtypes, particularly diffuse large B-cell lymphoma, warrant further study to assess CD81 expression and its role in the risk stratification of patients with diffuse large B-cell lymphoma.
View details for DOI 10.1016/j.humpath.2009.07.022
View details for Web of Science ID 000276493600015
View details for PubMedID 20004001
View details for PubMedCentralID PMC2813949
Lymphoma cell VEGFR2 expression detected by immunohistochemistry predicts poor overall survival in diffuse large B cell lymphoma treated with immunochemotherapy (R-CHOP)
BRITISH JOURNAL OF HAEMATOLOGY
2010; 148 (2): 235-244
Diffuse large B cell lymphoma (DLBCL) is clinically and biologically heterogeneous. In most cases of DLBCL, lymphoma cells co-express vascular endothelial growth factor (VEGF) and its receptors VEGFR1 and VEGFR2, suggesting autocrine in addition to angiogenic effects. We enumerated microvessel density and scored lymphoma cell expression of VEGF, VEGFR1, VEGFR2 and phosphorylated VEGFR2 in 162 de novo DLBCL patients treated with R-CHOP (rituximab, cyclophosphamide, vincristine, doxorubicin and prednisone)-like regimens. VEGFR2 expression correlated with shorter overall survival (OS) independent of International Prognostic Index (IPI) (P = 0.0028). Phosphorylated VEGFR2 (detected in 13% of cases) correlated with shorter progression-free survival (PFS, P = 0.044) and trended toward shorter OS on univariate analysis. VEGFR1 was not predictive of survival on univariate analysis, but it did correlate with better OS on multivariate analysis with VEGF, VEGFR2 and IPI (P = 0.036); in patients with weak VEGFR2, lack of VEGFR1 coexpression was significantly correlated with poor OS independent of IPI (P = 0.01). These results are concordant with our prior finding of an association of VEGFR1 with longer OS in DLBCL treated with chemotherapy alone. We postulate that VEGFR1 may oppose autocrine VEGFR2 signalling in DLBCL by competing for VEGF binding. In contrast to our prior results with chemotherapy alone, microvessel density was not prognostic of PFS or OS with R-CHOP-like therapy.
View details for DOI 10.1111/j.1365-2141.2009.07942.x
View details for Web of Science ID 000272884100006
View details for PubMedID 19821819
View details for PubMedCentralID PMC2809124
Prognostic significance of vascular endothelial growth factor (VEGF), VEGF receptors (VEGFR), and vascularity in diffuse large B-cell lymphoma treated with immunochemotherapy (R-CHOP)
45th Annual Meeting of the American-Society-of-Clinical-Oncology (ASCO)
AMER SOC CLINICAL ONCOLOGY. 2009
View details for Web of Science ID 000276606605490
The Transcription Factor LMO2 Is a Robust Marker of Vascular Endothelium and Vascular Neoplasms and Selected Other Entities
AMERICAN JOURNAL OF CLINICAL PATHOLOGY
2009; 131 (2): 264-278
The transcription factor LMO2 is involved in vascular and hematopoietic development and hematolymphoid neoplasia. We have demonstrated that LMO2 is expressed nearly ubiquitously in native and neoplastic vasculature, including lymphatics. LMO2 reactivity is otherwise virtually absent in nonhematolymphoid tissues except in breast myoepithelium, prostatic basal cells, and secretory phase endometrial glands. Vasculature is LMO2- in adult and fetal heart, brain of older adults, hepatic sinusoids, and hepatocellular carcinoma. LMO2 is uniformly expressed in benign vascular and lymphatic neoplasms and in most malignant vascular neoplasms with the exception of epithelioid vascular neoplasms of pleura and bone. Among nonvascular neoplasms, LMO2 reactivity is present in giant cell tumor of tendon sheath, juvenile xanthogranuloma, a subset of gastrointestinal stromal tumors, small round blue cell tumors, and myoepithelial-derived neoplasms. The restricted expression pattern, nuclear localization, and crisp staining of LMO2 in paraffin blocks make it an attractive candidate for the diagnostic immunohistochemistry laboratory.
View details for DOI 10.1309/AJCP5FP3NAXAXRJE
View details for Web of Science ID 000262540200013
View details for PubMedID 19141387
- VEGF-C: putting the 'lymph' back in lymphoma? LEUKEMIA & LYMPHOMA 2009; 50 (3): 311-312
CD81 Protein Is Expressed in Normal Germinal Center B-Cells and in Subtypes of Human Non-Hodgkin Lymphomas
98th Annual Meeting of the United-States-and-Canadian-Academy-of-Pathology
NATURE PUBLISHING GROUP. 2009: 275A–275A
View details for Web of Science ID 000262371501249
Lymphoma-Expressed VEGF-a,VEGFR-1, VEGFR-2, and Microvessel Density Are Not Predictive of Overall Survival in Follicular Lymphoma.
50th Annual Meeting of the American-Society-of-Hematology/ASH/ASCO Joint Symposium
AMER SOC HEMATOLOGY. 2008: 1290–90
View details for Web of Science ID 000262104704385
Neither CD68+Nor CD163+Macrophages Are Associated with Decreased Survival in Follicular Lymphoma
50th Annual Meeting of the American-Society-of-Hematology/ASH/ASCO Joint Symposium
AMER SOC HEMATOLOGY. 2008: 1284–84
View details for Web of Science ID 000262104704365
The transcription factor LMO2 is a robust marker of vascular endothelium and vascular neoplasms with rare exceptions
FEDERATION AMER SOC EXP BIOL. 2008
View details for Web of Science ID 000208467800092
Ameloblastoma, calcifying epithelial odontogenic tumor, and glandular odontogenic cyst show a distinctive immunophenotype with some myoepithelial antigen expression
JOURNAL OF ORAL PATHOLOGY & MEDICINE
2008; 37 (3): 177-184
Odontogenic neoplasms have some morphologic overlap with salivary gland neoplasms, many of which show myoepithelial differentiation. In the 1980s, an ultrastructural study identified a population of myoepithelial-like cells in calcifying epithelial odontogenic tumor. Myoepithelial derived tumors have since been shown to have distinct immunohistochemical profiles.We examined a series of odontogenic neoplasms, including 11 ameloblastomas, four calcifying epithelial odontogenic tumors, five glandular odontogenic cysts (GOCs), and five keratocystic odontogenic tumors with a panel of myoepithelial-associated immunohistochemical stains. We also assessed representative control examples of oral mucosa, odontogenic rests, and dentigerous cysts.All of the neoplastic and non-neoplastic oral epithelium-derived entities share a p63-positive, high molecular weight cytokeratin (CK5/6)-positive immunophenotype. Calponin reactivity was at least focally present in two of four calcifying epithelial odontogenic tumors, three of five GOCs, and 10 of 11 ameloblastomas; the sole completely non-reactive ameloblastoma represents a lung metastasis. One case of calcifying epithelial odontogenic tumor was focally positive for glial fibrillary acidic protein. However, other more definitive markers of myoepithelial differentiation, including S-100 and smooth muscle actin, were negative. Two of three calcifying epithelial odontogenic tumors and five of five GOCs were also positive for a low molecular weight cytokeratin (CK7).Ameloblastomas, GOCs, and calcifying epithelial odontogenic tumors show a distinctive immunophenotype which overlaps with that of myoepithelial-derived salivary gland neoplasms but does not provide definitive support for myoepithelial differentiation.
View details for DOI 10.1111/j.1600-0714.2007.00613.x
View details for Web of Science ID 000252812000008
View details for PubMedID 18251942
LMO2 protein expression predicts survival in patients with diffuse large B-Cell lymphoma treated with anthracycline-based chemotherapy with and without rituximab
JOURNAL OF CLINICAL ONCOLOGY
2008; 26 (3): 447-454
The heterogeneity of diffuse large B-cell lymphoma (DLBCL) has prompted the search for new markers that can accurately separate prognostic risk groups. We previously showed in a multivariate model that LMO2 mRNA was a strong predictor of superior outcome in DLBCL patients. Here, we tested the prognostic impact of LMO2 protein expression in DLBCL patients treated with anthracycline-based chemotherapy with or without rituximab.DLBCL patients treated with anthracycline-based chemotherapy alone (263 patients) or with the addition of rituximab (80 patients) were studied using immunohistochemistry for LMO2 on tissue microarrays of original biopsies. Staining results were correlated with outcome.In anthracycline-treated patients, LMO2 protein expression was significantly correlated with improved overall survival (OS) and progression-free survival (PFS) in univariate analyses (OS, P = .018; PFS, P = .010) and was a significant predictor independent of the clinical International Prognostic Index (IPI) in multivariate analysis. Similarly, in patients treated with the combination of anthracycline-containing regimens and rituximab, LMO2 protein expression was also significantly correlated with improved OS and PFS (OS, P = .005; PFS, P = .009) and was a significant predictor independent of the IPI in multivariate analysis.We conclude that LMO2 protein expression is a prognostic marker in DLBCL patients treated with anthracycline-based regimens alone or in combination with rituximab. After further validation, immunohistologic analysis of LMO2 protein expression may become a practical assay for newly diagnosed DLBCL patients to optimize their clinical management.
View details for DOI 10.1200/JCO.2007.13.0690
View details for Web of Science ID 000254177200020
View details for PubMedID 18086797
Prognostic significance of VEGF, VEGF receptors, and microvessel density in diffuse large B cell lymphoma treated with anthracycline-based chemotherapy
2008; 88 (1): 38-47
Vascular endothelial growth factor-mediated signaling has at least two potential roles in diffuse large B cell lymphoma: potentiation of angiogenesis, and potentiation of lymphoma cell proliferation and/or survival induced by autocrine vascular endothelial growth factor receptor-mediated signaling. We have recently shown that diffuse large B cell lymphomas expressing high levels of vascular endothelial growth factor protein also express high levels of vascular endothelial growth factor receptor-1 and vascular endothelial growth factor receptor-2. We have now assessed a larger multi-institutional cohort of patients with de novo diffuse large B cell lymphoma treated with anthracycline-based therapy to address whether tumor vascularity, or expression of vascular endothelial growth factor protein and its receptors, contribute to patient outcomes. Our results show that increased tumor vascularity is associated with poor overall survival (P=0.047), and is independent of the international prognostic index. High expression of vascular endothelial growth factor receptor-1 by lymphoma cells by contrast is associated with improved overall survival (P=0.044). The combination of high vascular endothelial growth factor and vascular endothelial growth factor receptor-1 protein expression by lymphoma cells identifies a subgroup of patients with improved overall (P=0.003) and progression-free (P=0.026) survival; these findings are also independent of the international prognostic index. The prognostic significance of overexpression of this ligand-receptor pair suggests that autocrine signaling via vascular endothelial growth factor receptor-1 may represent a survival or proliferation pathway in diffuse large B cell lymphoma. Dependence on autocrine vascular endothelial growth factor receptor-1-mediated signaling may render a subset of diffuse large B-cell lymphomas susceptible to anthracycline-based therapy.
View details for DOI 10.1038/labinvest.3700697
View details for Web of Science ID 000251820600004
View details for PubMedID 17998899
Microvessel density and expression of vascular endothelial growth factor and its receptors in diffuse large B-cell lymphoma subtypes
AMERICAN JOURNAL OF PATHOLOGY
2007; 170 (4): 1362-1369
Angiogenesis is known to play a major role in neoplasia, including hematolymphoid neoplasia. We assessed the relationships among angiogenesis and expression of vascular endothelial growth factor and its receptors in the context of clinically and biologically relevant subtypes of diffuse large B-cell lymphoma using immunohistochemical evaluation of tissue microarrays. We found that diffuse large B-cell lymphoma specimens showing higher local vascular endothelial growth factor expression showed correspondingly higher microvessel density, implying that lymphoma cells induce local tumor angiogenesis. In addition, local vascular endothelial growth factor expression was higher in those specimens showing higher expression of the receptors of the growth factor, suggesting an autocrine growth-promoting feedback loop. The germinal center-like and nongerminal center-like subtypes of diffuse large B-cell lymphoma were biologically and prognostically distinct. Interestingly, only in the more clinically aggressive nongerminal center-like subtype were microvessel densities significantly higher in specimens showing higher vascular endothelial growth factor expression; the same was true for the finding of higher vascular endothelial growth factor receptor-1 expression in conjunction with higher vascular endothelial growth factor expression. These differences may have important implications for the responsiveness of the two diffuse large B-cell lymphoma subtypes to anti-vascular endothelial growth factor and anti-angiogenic therapies.
View details for DOI 10.2353/ajpath.2007.060901
View details for Web of Science ID 000245233000022
View details for PubMedID 17392174
Identification of the regions of PECAM-1 involved in beta- and gamma-catenin associations
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
2005; 329 (4): 1225-1233
Platelet endothelial cell adhesion molecule-1 (PECAM-1) binds tyrosine-phosphorylated beta-catenin and modulates beta-catenin localization and sequestration. The biological significance of this interaction, while still unclear, it has been postulated to be involved in modulating adherens junction dynamics in response to perturbants [J. Clin. Invest. 109 (2002) 383]. Here we demonstrate that tyrosine-phosphorylated beta-catenin, and to a lesser extent unphosphorylated beta-catenin, interact with a portion of the cytoplasmic domain of PECAM-1 encoded by exon 15. Using RT-PCR, we obtained products representing alternatively spliced PECAM-1 isoforms from mouse kidney total mRNA and generated PECAM-1-GST constructs expressing full length and naturally occurring alternatively spliced PECAM-1 variants. Co-precipitation assays revealed that the protein sequence encoded by exon 15 is necessary for beta-catenin binding. Transfections using deletion mutants confirmed the importance of the exon 15 sequence in this interaction. In contrast, gamma-catenin-PECAM-1 interactions are thought to be modulated by an as yet undefined PECAM-1 serine phosphorylation and appear to mediate dynamic PECAM-1 intermediate filament cytoskeletal interactions [J. Biol. Chem. 275 (2000) 21435]. Here we demonstrate that the PECAM-1-gamma-catenin interaction occurs via an exon 13-mediated process. GST-pull-down assays illustrated the importance of the exon 13 sequence in this interaction. Further, using site-directed mutagenesis of S(673) to C and D and S(669 and 670) to C, we confirmed the importance of S(673) and its phosphorylation state as a mediator of gamma-catenin-PECAM-1 binding. Our studies define the exons of the PECAM-1 cytoplasmic domain that is involved in mediating these PECAM-1-catenin family member interactions and will allow investigators to better define the biological functions resulting from these interactions.
View details for DOI 10.1016/j.bbrc.2005.02.095
View details for Web of Science ID 000227886300008
View details for PubMedID 15766557
Platelet endothelial cell adhesion molecule-1 modulates endothelial cell motility through the small G-protein Rho
2003; 17 (11): 1458-1469
Platelet endothelial cell adhesion molecule-1 (PECAM-1), an immunoglobulin family vascular adhesion molecule, is involved in endothelial cell migration and angiogenesis (1, 2). We found that endothelial cells lacking PECAM-1 exhibit increased single cell motility and extension formation but poor wound healing migration, reminiscent of cells in which Rho activity has been suppressed by overexpressing a GTPase-activating protein (3). The ability of PECAM-1 to restore wound healing migration to PECAM-1-deficient cells was independent of its extracellular domain or signaling via its immunoreceptor tyrosine-based inhibitory motif. PECAM-1-deficient endothelial cells had a selective defect in RhoGTP loading, and inhibition of Rho activity mimicked the PECAM-1-deficient phenotype of increased chemokinetic single cell motility at the expense of coordinated wound healing migration. The wound healing advantage of PECAM-1-positive endothelial cells was not only Rho mediated but pertussis toxin inhibitable, characteristic of migration mediated by heterotrimeric G-protein-linked seven-transmembrane receptor signaling such as signaling in response to the serum sphingolipid sphingosine-1-phosphate (S1P) (4, 5). Indeed, we found that the wound healing defect of PECAM-1 null endothelial cells is minimized in sphingolipid-depleted media; moreover, PECAM-1 null endothelial cells fail to increase their migration in response to S1P. We have also found that PECAM-1 localizes to rafts and that in its absence heterotrimeric G-protein components are differentially recruited to rafts, providing a potential mechanism for PECAM-1-mediated coordination of S1P signaling. PECAM-1 may thus support the effective S1P/RhoGTP signaling required for wound healing endothelial migration by allowing for the spatially directed, coordinated activation of Galpha signaling pathways.
View details for DOI 10.1096/fj.02-1040com
View details for Web of Science ID 000185345100039
View details for PubMedID 12890700
Elevated glucose inhibits VEGF-A-mediated endocardial cushion formation: modulation by PECAM-1 and MMP-2
JOURNAL OF CELL BIOLOGY
2003; 160 (4): 605-615
Atrioventricular (AV) septal defects resulting from aberrant endocardial cushion (EC) formation are observed at increased rates in infants of diabetic mothers. EC formation occurs via an epithelial-mesenchymal transformation (EMT), involving transformation of endocardial cells into mesenchymal cells, migration, and invasion into extracellular matrix. Here, we report that elevated glucose inhibits EMT by reducing myocardial vascular endothelial growth factor A (VEGF-A). This effect is reversed with exogenous recombinant mouse VEGF-A165, whereas addition of soluble VEGF receptor-1 blocks EMT. We show that disruption of EMT is associated with persistence of platelet endothelial cell adhesion molecule-1 (PECAM-1) and decreased matrix metalloproteinase-2 (MMP-2) expression. These findings correlate with retention of a nontransformed endocardial sheet and lack of invasion. The MMP inhibitor GM6001 blocks invasion, whereas explants from PECAM-1 deficient mice exhibit MMP-2 induction and normal EMT in high glucose. PECAM-1-negative endothelial cells are highly motile and express more MMP-2 than do PECAM-1-positive endothelial cells. During EMT, loss of PECAM-1 similarly promotes single cell motility and MMP-2 expression. Our findings suggest that high glucose-induced inhibition of AV cushion morphogenesis results from decreased myocardial VEGF-A expression and is, in part, mediated by persistent endocardial cell PECAM-1 expression and failure to up-regulate MMP-2 expression.
View details for DOI 10.1083/jcb.200209014
View details for Web of Science ID 000181090200014
View details for PubMedID 12591918
Platelet-endothelial cell adhesion molecule-1 modulates endothelial migration through its immunoreceptor tyrosine-based inhibitory motif
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
2003; 301 (1): 243-249
Coordinated migration of endothelial cells models the remodeling of existing endothelia as well as angiogenesis and vasculogenesis. Platelet-endothelial cell adhesion molecule-1, PECAM-1, a transmembrane endothelial adhesion protein, binds and activates the tyrosine phosphatase SHP-2 via phosphotyrosines 663 and 686. PECAM-1 phosphorylation and recruitment of SHP-2 are regulated by cell-cell and cell-substrate adhesion. We found that PECAM-1 is dephosphorylated on tyrosine 686 during endothelial migration, resulting in diffuse dispersal of PECAM-1 and SHP-2. Overexpression of native PECAM-1 slowed, and nonphosphorylatable PECAM-1 increased, endothelial migration, implying that the SHP-2-regulatory phosphotyrosines negatively regulate migration. Using differentially phosphorylated recombinant proteins we found that phosphotyrosine 686 preferentially mediates binding and 663 mediates activation of SHP-2 by PECAM-1. In PECAM-1-null endothelial cells, SHP-2 bound and dephosphorylated an alternative set of phosphoproteins and its distribution to the cytoskeletal fraction was significantly decreased. Tyrosine phosphorylation of beta-catenin and focal adhesion kinase was increased in endothelial cells overexpressing nonphosphorylatable PECAM-1. Thus homophilically engaged, tyrosine-phosphorylated PECAM-1 locally activates SHP-2 at cell-cell junctions; with disruption of the endothelial monolayer, selective dephosphorylation of PECAM-1 leads to redistribution of SHP-2 and pro-migratory changes in phosphorylation of cytoskeletal and focal contact components.
View details for DOI 10.1016/S0006-291X(02)02982-0
View details for Web of Science ID 000181052800040
View details for PubMedID 12535670
Interpreting a medium-resolution model of tubulin: Comparison of zinc-sheet and microtubule structure
JOURNAL OF MOLECULAR BIOLOGY
1996; 262 (4): 485-501
We previously used electron crystallography of zinc-induced two-dimensional crystalline sheets of tubulin to construct a medium-resolution three dimensional (3-D) reconstruction (at 6.5 A) of this protein. Here we present an improved model, and extend the interpretation to correlate it to microtubule structure. Secondary sequence predictions and projection density maps of subtilisin-cleaved tubulin provide information on the location of the C-terminal portion, which has been suggested to be involved in the binding of microtubule-associated proteins. The zinc-sheet tubulin model is compared to microtubules in two ways; comparison of electron diffraction from the zinc-sheets to electron diffraction from microtubules, and by docking the zinc-sheet protofilament 3-D model into a helical reconstruction from ice-embedded microtubules. By correlating the zinc-sheet protofilament to a reconstruction of axonemal protofilaments, we assigned polarity to the protofilament in our model. The polarity assignment together with our model for dimer boundaries and the assignment of alpha- and beta-monomers in our reconstruction, provides a microtubule model where the alpha-monomer crowns the plus- (or fast-growing) end of the microtubule and contact is made in the centrosome with gamma-tubulin via the beta-monomer.
View details for Web of Science ID A1996VK74900009
View details for PubMedID 8893858