Bio


Oscar is an academic hematopathologist who completed anatomic and clinical pathology residency and hematopathology fellowship at Stanford in 2020. Prior to Stanford, he received his MD and PhD from UCLA. His interests include immunology, the pathogenesis and diagnosis of lymphomas, and global health.

Clinical Focus


  • Hematopathology
  • Anatomical and Clinical Pathology
  • Anatomic and Clinical Pathology

Academic Appointments


Professional Education


  • Board Certification: American Board of Pathology, Anatomic and Clinical Pathology (2020)
  • Board Certification: American Board of Pathology, Hematopathology (2021)
  • Fellowship: Stanford University Hemapathology Fellowship (2018) CA
  • Residency: Stanford University Pathology Residency (2020) CA
  • Medical Education: UCLA David Geffen School Of Medicine Registrar (2015) CA
  • M.D., University of California, Los Angeles (2015)
  • Ph.D, University of California, Los Angeles, Immunology (2013)

All Publications


  • Immune imprinting, breadth of variant recognition, and germinal center response in human SARS-CoV-2 infection and vaccination. Cell Röltgen, K., Nielsen, S. C., Silva, O., Younes, S. F., Zaslavsky, M., Costales, C., Yang, F., Wirz, O. F., Solis, D., Hoh, R. A., Wang, A., Arunachalam, P. S., Colburg, D., Zhao, S., Haraguchi, E., Lee, A. S., Shah, M. M., Manohar, M., Chang, I., Gao, F., Mallajosyula, V., Li, C., Liu, J., Shoura, M. J., Sindher, S. B., Parsons, E., Dashdorj, N. J., Dashdorj, N. D., Monroe, R., Serrano, G. E., Beach, T. G., Chinthrajah, R. S., Charville, G. W., Wilbur, J. L., Wohlstadter, J. N., Davis, M. M., Pulendran, B., Troxell, M. L., Sigal, G. B., Natkunam, Y., Pinsky, B. A., Nadeau, K. C., Boyd, S. D. 2022

    Abstract

    During the SARS-CoV-2 pandemic, novel and traditional vaccine strategies have been deployed globally. We investigated whether antibodies stimulated by mRNA vaccination (BNT162b2), including third-dose boosting, differ from those generated by infection or adenoviral (ChAdOx1-S and Gam-COVID-Vac) or inactivated viral (BBIBP-CorV) vaccines. We analyzed human lymph nodes after infection or mRNA vaccination for correlates of serological differences. Antibody breadth against viral variants is lower after infection compared with all vaccines evaluated but improves over several months. Viral variant infection elicits variant-specific antibodies, but prior mRNA vaccination imprints serological responses toward Wuhan-Hu-1 rather than variant antigens. In contrast to disrupted germinal centers (GCs) in lymph nodes during infection, mRNA vaccination stimulates robust GCs containing vaccine mRNA and spike antigen up to 8 weeks postvaccination in some cases. SARS-CoV-2 antibody specificity, breadth, and maturation are affected by imprinting from exposure history and distinct histological and antigenic contexts in infection compared with vaccination.

    View details for DOI 10.1016/j.cell.2022.01.018

    View details for PubMedID 35148837

  • Low-cost transcriptional diagnostic to accurately categorize lymphomas in low- and middle-income countries. Blood advances Valvert, F. n., Silva, O. n., Solórzano-Ortiz, E. n., Puligandla, M. n., Siliézar Tala, M. M., Guyon, T. n., Dixon, S. L., López, N. n., López, F. n., Carías Alvarado, C. C., Terbrueggen, R. n., Stevenson, K. E., Natkunam, Y. n., Weinstock, D. M., Briercheck, E. L. 2021; 5 (10): 2447–55

    Abstract

    Inadequate diagnostics compromise cancer care across lower- and middle-income countries (LMICs). We hypothesized that an inexpensive gene expression assay using paraffin-embedded biopsy specimens from LMICs could distinguish lymphoma subtypes without pathologist input. We reviewed all biopsy specimens obtained at the Instituto de Cancerología y Hospital Dr. Bernardo Del Valle in Guatemala City between 2006 and 2018 for suspicion of lymphoma. Diagnoses were established based on the World Health Organization classification and then binned into 9 categories: nonmalignant, aggressive B-cell, diffuse large B-cell, follicular, Hodgkin, mantle cell, marginal zone, natural killer/T-cell, or mature T-cell lymphoma. We established a chemical ligation probe-based assay (CLPA) that quantifies expression of 37 genes by capillary electrophoresis with reagent/consumable cost of approximately $10/sample. To assign bins based on gene expression, 13 models were evaluated as candidate base learners, and class probabilities from each model were then used as predictors in an extreme gradient boosting super learner. Cases with call probabilities < 60% were classified as indeterminate. Four (2%) of 194 biopsy specimens in storage <3 years experienced assay failure. Diagnostic samples were divided into 70% (n = 397) training and 30% (n = 163) validation cohorts. Overall accuracy for the validation cohort was 86% (95% confidence interval [CI]: 80%-91%). After excluding 28 (17%) indeterminate calls, accuracy increased to 94% (95% CI: 89%-97%). Concordance was 97% for a set of high-probability calls (n = 37) assayed by CLPA in both the United States and Guatemala. Accuracy for a cohort of relapsed/refractory biopsy specimens (n = 39) was 79% and 88%, respectively, after excluding indeterminate cases. Machine-learning analysis of gene expression accurately classifies paraffin-embedded lymphoma biopsy specimens and could transform diagnosis in LMICs.

    View details for DOI 10.1182/bloodadvances.2021004347

    View details for PubMedID 33988700

  • Geographic EBV variants confound disease-specific variant interpretation and predict variable immune therapy responses. Blood advances Briercheck, E. L., Ravishankar, S., Ahmed, E. H., Carias Alvarado, C. C., Silva, O., Solórzano-Ortiz, E., Siliezar Tala, M. M., Stevenson, P. A., Xu, Y., Wohns, A. W., Enriquez-Vera, D., Barrionuevo, C., Yu, S. C., Freud, A. G., Weigel, C., Oakes, C. C., Weinstock, D. M., Klimaszewski, H. L., Ngankeu, A., Mutalima, N., Samayoa-Reyes, G., Newton, R., Rochford, R., Valvert, F., Natkunam, Y., Shustov, A., Baiocchi, R. A., Warren, E. H. 2024

    Abstract

    Epstein-Barr virus (EBV) is a potent carcinogen linked to hematologic and solid malignancies, causing significant global morbidity and mortality. Therapy using allogeneic EBV-specific lymphocytes shows promise in certain populations, but the impact of EBV genome variation on these strategies remains unexplored. To address this, we sequenced 217 EBV genomes, including hematologic malignancies from Guatemala, Peru, Malawi, and Taiwan, and analyzed them alongside 1,307 publicly available EBV genomes from cancer, non-malignant diseases, and healthy individuals across Africa, Asia, Europe, North America, and South America. These included the first NK/T-cell lymphoma (NKTCL) EBV genomes reported outside East Asia. Our findings indicate that previously proposed EBV genome variants specific to certain cancer types are more closely tied to geographic origin than cancer histology. This included variants previously reported to be specific to NKTCL but were prevalent in EBV genomes from other cancer types and healthy individuals in East Asia. After controlling for geographic region, we did identify multiple NKTCL-specific variants associated with a 7.8- to 21.9- fold increased risk. We also observed frequent variations in EBV genomes affecting peptide sequences previously reported to bind common MHC alleles. Finally, we found several non-synonymous variants spanning the coding sequences of current vaccine targets BALF4, BKRF2, BLLF1, BXLF2, BZLF1, and BZLF2. These results highlight the need to consider geographic variation in EBV genomes when devising strategies for exploiting adaptive immune responses against EBV-related cancers, ensuring greater global effectiveness and equity in prevention and treatment.

    View details for DOI 10.1182/bloodadvances.2023012461

    View details for PubMedID 38815238

  • p53 immunohistochemistry as an ancillary tool for rapid assessment of residual disease in TP53-mutated acute myeloid leukemia and myelodysplastic syndromes. American journal of clinical pathology Brar, N., Lawrence, L., Fung, E., Zehnder, J. L., Greenberg, P. L., Mannis, G. N., Zhang, T. Y., Gratzinger, D., Oak, J., Silva, O., Kurzer, J., Tan, B., Menke, J. R., Fernandez-Pol, S. 2024

    Abstract

    Measurable residual disease flow cytometry (MRD-FC) and molecular studies are the most sensitive methods for detecting residual malignant populations after therapy for TP53-mutated acute myeloid leukemia and myelodysplastic neoplasms (TP53+ AML/MDS). However, their sensitivity is limited in suboptimal aspirates or when the immunophenotype of the neoplastic blasts overlaps with erythroids or normal maturing myeloid cells. In this study, we set out to determine if p53 immunohistochemistry (IHC) correlates with MRD-FC and next-generation sequencing (NGS) in the posttherapy setting and to determine the utility of p53 IHC to detect residual disease in the setting of negative or equivocal MRD-FC.We retrospectively identified 28 pre- and posttherapy bone marrow biopsy specimens from 9 patients with TP53+ AML/MDS and a p53 overexpressor phenotype by IHC (strong 3+ staining at initial diagnosis). Next-generation sequencing and/or MRD-FC results were collected for each specimen.Using a threshold of more than ten 2-3+ cells in any one 400× field, p53 IHC detected residual disease with a sensitivity of 94% and a specificity of 89%. The threshold used in this study showed a high degree of concordance among 6 blinded pathologists (Fleiss κ = 0.97).Our study suggests that p53 IHC can be used as a rapid tool (within 24 hours) to aid in the detection of residual disease that may complement MRD-FC or NGS in cases in which the flow cytometry immunophenotype is equivocal and/or the bone marrow aspirate is suboptimal.

    View details for DOI 10.1093/ajcp/aqae034

    View details for PubMedID 38643353

  • The clinical, molecular, and prognostic features of the 2022 WHO and ICC classification systems for myelodysplastic neoplasms. Leukemia research Khanna, V., Lu, R., Kumar, J., Molina, A., Stehr, H., Spiteri, E., Spinner, M., Silva, O., Fernandez-Pol, S., Tan, B., Greenberg, P. L. 2023; 136: 107433

    Abstract

    Myelodysplastic neoplasms (MDS) are clonal disorders of bone marrow failure exhibiting a variable risk of progression to acute myeloid leukemia. MDS exhibit certain prognostic genetic or cytogenetic abnormalities, an observation that has led to both the pathologic reclassification of MDS in the 2022 World Health Organization (WHO) and International Consensus Classification (ICC) systems, as well as to an updated prognostic schema, the Molecular International Prognostic Scoring System (IPSS-M). This single-institution study characterized the molecular patterns and clinical outcomes associated with the 2022 WHO and ICC classification schemas to assess their clinical utility. Strikingly, with the exception of one individual, all 210 patients in our cohort were classified into analogous categories by the two pathologic/diagnostic schemas. Most patients (70%) were classified morphologically while the remaining 30% had genetically classified disease by both criteria. Prognostic risk, as assessed by the IPSS-M score was highest in patients with MDS with biallelic/multi-hit TP53 mutations and lowest in pts with MDS-SF3B1. Median leukemia-free survival (LFS) was shortest for those with MDS with biallelic/multi-hit TP53 (0.7 years) and longest for those with MDS with low blasts (LFS not reached). These data demonstrate the clear ability of the 2022 WHO and ICC classifications to organize MDS patients into distinct prognostic risk groups and further show that both classification systems share more similarities than differences. Incorporation of the IPSS-M and IPSS-R features provide additive prognostic and survival components to both the WHO and ICC classifications, which together enhance their utility for evaluating and treating MDS patients.

    View details for DOI 10.1016/j.leukres.2023.107433

    View details for PubMedID 38154193

  • Somatostatin Receptor (SSTR2) Expression in EBV-Positive and EBV-Negative Lymphomas from Guatemala Brar, N., Charville, G., Natkunam, Y., Valvert, F., Briercheck, E., Silva, O. ELSEVIER SCIENCE INC. 2023: S1102-S1104
  • Localization, Quantity, and Persistence of SARS-CoV2 Vaccine mRNA and Spike Antigen in Lymph Nodes of Pediatric Vaccinees Miller, T., Wang, A., Colburg, D., Boyd, S., Silva, O. ELSEVIER SCIENCE INC. 2023: S1196-S1197
  • Clinicopathologic Features of Human Monkeypox Lymphadenitis. Histopathology Qian, Z. J., Gong, R., Mann, D. S., Walding, K., Miller, T., Nicholas, V., Kappagoda, S., Pinsky, B. A., Silva, O., Lau, H. D. 2023

    View details for DOI 10.1111/his.14878

    View details for PubMedID 36734592

  • Hepatosplenic T-cell lymphoma with STAT5B and SETD2 mutations recurring as cells with NK-cell immunophenotype. Blood Khodadoust, M., Silva, O. 2023; 141 (5): 555

    View details for DOI 10.1182/blood.2022018200

    View details for PubMedID 36729542

  • Correlation of Mutational Profiles and Cytogenetics with Morphologic Dysplasia in Myelodysplastic Syndromes Kumar, J., Khanna, V., Lu, R., Stehr, H., Spinner, M. A., Silva, O., Fernandez-Pol, S., Oak, J. S., Greenberg, P. L., Tan, B. AMER SOC HEMATOLOGY. 2022: 4053-4055
  • Characterization of Clinical, Molecular, and Prognostic Features of the WHO 2022 Classification System for Myelodysplastic Neoplasms (MDS) Khanna, V., Lu, R., Kumar, J., Stehr, H., Spinner, M. A., Silva, O., Fernandez-Pol, S., Oak, J. S., Tan, B., Greenberg, P. L. AMER SOC HEMATOLOGY. 2022: 6955-6957
  • The Tabula Sapiens: A multiple-organ, single-cell transcriptomic atlas of humans. Science (New York, N.Y.) Jones, R. C., Karkanias, J., Krasnow, M. A., Pisco, A. O., Quake, S. R., Salzman, J., Yosef, N., Bulthaup, B., Brown, P., Harper, W., Hemenez, M., Ponnusamy, R., Salehi, A., Sanagavarapu, B. A., Spallino, E., Aaron, K. A., Concepcion, W., Gardner, J. M., Kelly, B., Neidlinger, N., Wang, Z., Crasta, S., Kolluru, S., Morri, M., Pisco, A. O., Tan, S. Y., Travaglini, K. J., Xu, C., Alcántara-Hernández, M., Almanzar, N., Antony, J., Beyersdorf, B., Burhan, D., Calcuttawala, K., Carter, M. M., Chan, C. K., Chang, C. A., Chang, S., Colville, A., Crasta, S., Culver, R. N., Cvijović, I., D'Amato, G., Ezran, C., Galdos, F. X., Gillich, A., Goodyer, W. R., Hang, Y., Hayashi, A., Houshdaran, S., Huang, X., Irwin, J. C., Jang, S., Juanico, J. V., Kershner, A. M., Kim, S., Kiss, B., Kolluru, S., Kong, W., Kumar, M. E., Kuo, A. H., Leylek, R., Li, B., Loeb, G. B., Lu, W. J., Mantri, S., Markovic, M., McAlpine, P. L., de Morree, A., Morri, M., Mrouj, K., Mukherjee, S., Muser, T., Neuhöfer, P., Nguyen, T. D., Perez, K., Phansalkar, R., Pisco, A. O., Puluca, N., Qi, Z., Rao, P., Raquer-McKay, H., Schaum, N., Scott, B., Seddighzadeh, B., Segal, J., Sen, S., Sikandar, S., Spencer, S. P., Steffes, L. C., Subramaniam, V. R., Swarup, A., Swift, M., Travaglini, K. J., Van Treuren, W., Trimm, E., Veizades, S., Vijayakumar, S., Vo, K. C., Vorperian, S. K., Wang, W., Weinstein, H. N., Winkler, J., Wu, T. T., Xie, J., Yung, A. R., Zhang, Y., Detweiler, A. M., Mekonen, H., Neff, N. F., Sit, R. V., Tan, M., Yan, J., Bean, G. R., Charu, V., Forgó, E., Martin, B. A., Ozawa, M. G., Silva, O., Tan, S. Y., Toland, A., Vemuri, V. N., Afik, S., Awayan, K., Botvinnik, O. B., Byrne, A., Chen, M., Dehghannasiri, R., Detweiler, A. M., Gayoso, A., Granados, A. A., Li, Q., Mahmoudabadi, G., McGeever, A., de Morree, A., Olivieri, J. E., Park, M., Pisco, A. O., Ravikumar, N., Salzman, J., Stanley, G., Swift, M., Tan, M., Tan, W., Tarashansky, A. J., Vanheusden, R., Vorperian, S. K., Wang, P., Wang, S., Xing, G., Xu, C., Yosef, N., Alcántara-Hernández, M., Antony, J., Chan, C. K., Chang, C. A., Colville, A., Crasta, S., Culver, R., Dethlefsen, L., Ezran, C., Gillich, A., Hang, Y., Ho, P. Y., Irwin, J. C., Jang, S., Kershner, A. M., Kong, W., Kumar, M. E., Kuo, A. H., Leylek, R., Liu, S., Loeb, G. B., Lu, W. J., Maltzman, J. S., Metzger, R. J., de Morree, A., Neuhöfer, P., Perez, K., Phansalkar, R., Qi, Z., Rao, P., Raquer-McKay, H., Sasagawa, K., Scott, B., Sinha, R., Song, H., Spencer, S. P., Swarup, A., Swift, M., Travaglini, K. J., Trimm, E., Veizades, S., Vijayakumar, S., Wang, B., Wang, W., Winkler, J., Xie, J., Yung, A. R., Artandi, S. E., Beachy, P. A., Clarke, M. F., Giudice, L. C., Huang, F. W., Huang, K. C., Idoyaga, J., Kim, S. K., Krasnow, M., Kuo, C. S., Nguyen, P., Quake, S. R., Rando, T. A., Red-Horse, K., Reiter, J., Relman, D. A., Sonnenburg, J. L., Wang, B., Wu, A., Wu, S. M., Wyss-Coray, T. 2022; 376 (6594): eabl4896

    Abstract

    Molecular characterization of cell types using single-cell transcriptome sequencing is revolutionizing cell biology and enabling new insights into the physiology of human organs. We created a human reference atlas comprising nearly 500,000 cells from 24 different tissues and organs, many from the same donor. This atlas enabled molecular characterization of more than 400 cell types, their distribution across tissues, and tissue-specific variation in gene expression. Using multiple tissues from a single donor enabled identification of the clonal distribution of T cells between tissues, identification of the tissue-specific mutation rate in B cells, and analysis of the cell cycle state and proliferative potential of shared cell types across tissues. Cell type-specific RNA splicing was discovered and analyzed across tissues within an individual.

    View details for DOI 10.1126/science.abl4896

    View details for PubMedID 35549404

  • Case Report: Castleman Disease With an Associated Stromal Spindle Cell Proliferation, PDGFRB Mutation and p53 Expression: Clonal Origins of a Rare Disease. Frontiers in oncology Singh, K. I., Gollapudi, S., Kumar, J., Butzmann, A., Small, C., Kreimer, S., Saglam, E. A., Warnke, R., Silva, O., Ohgami, R. S. 2022; 12: 857606

    Abstract

    Castleman disease (CD) is a rare lymphoproliferative disorder with distinct clinical subtypes. However, our understanding of the underlying pathogenesis of particular subtypes of CD remains unclear. While the characteristic morphologic changes within UCD, including occasional cases of overgrowth of spindled stromal and follicular dendritic cells have been described, the nature and origin of these spindle cells remain elusive. Few reports have suggested that underlying stromal cells in UCD are clonally neoplastic and may be of fibroblastic reticular cell (FRC) or follicular dendritic cell (FDC) origins given their close clonal relationship. Although certain histomorphologic features may aid diagnosis, there are no specific biomarkers that can differentiate a reactive process mimicking UCD from true UCD. Hence, we describe an index case with morphology consistent with the hyaline vascular subtype of UCD with concomitant atypical smooth muscle actin (SMA)-positive stromal spindle cell proliferation containing a recurrent PDGFRB N666S mutation and upregulation of p53 expression. Further analysis of 21 additional cases of UCD identified increased p53 expression by digital image analysis and SMA positive stromal cells predominantly within the paracortical and intrafollicular areas further strengthening the hypothesis of the stromal cellular derivation and origins of UCD.

    View details for DOI 10.3389/fonc.2022.857606

    View details for PubMedID 35494027

    View details for PubMedCentralID PMC9043324

  • Cell types of origin of the cell-free transcriptome. Nature biotechnology Vorperian, S. K., Moufarrej, M. N., Tabula Sapiens Consortium, Quake, S. R., Jones, R. C., Karkanias, J., Krasnow, M., Pisco, A. O., Quake, S. R., Salzman, J., Yosef, N., Bulthaup, B., Brown, P., Harper, W., Hemenez, M., Ponnusamy, R., Salehi, A., Sanagavarapu, B. A., Spallino, E., Aaron, K. A., Concepcion, W., Gardner, J. M., Kelly, B., Neidlinger, N., Wang, Z., Crasta, S., Kolluru, S., Morri, M., Tan, S. Y., Travaglini, K. J., Xu, C., Alcantara-Hernandez, M., Almanzar, N., Antony, J., Beyersdorf, B., Burhan, D., Calcuttawala, K., Carter, M. M., Chan, C. K., Chang, C. A., Chang, S., Colville, A., Culver, R. N., Cvijovic, I., D'Amato, G., Ezran, C., Galdos, F. X., Gillich, A., Goodyer, W. R., Hang, Y., Hayashi, A., Houshdaran, S., Huang, X., Irwin, J. C., Jang, S., Juanico, J. V., Kershner, A. M., Kim, S., Kiss, B., Kong, W., Kumar, M. E., Kuo, A. H., Leylek, R., Li, B., Loeb, G. B., Lu, W., Mantri, S., Markovic, M., McAlpine, P. L., de Morree, A., Mrouj, K., Mukherjee, S., Muser, T., Neuhofer, P., Nguyen, T. D., Perez, K., Phansalkar, R., Puluca, N., Qi, Z., Rao, P., Raquer-McKay, H., Schaum, N., Scott, B., Seddighzadeh, B., Segal, J., Sen, S., Sikandar, S., Spencer, S. P., Steffes, L., Subramaniam, V. R., Swarup, A., Swift, M., Van Treuren, W., Trimm, E., Veizades, S., Vijayakumar, S., Vo, K. C., Vorperian, S. K., Wang, W., Weinstein, H. N., Winkler, J., Wu, T. T., Xie, J., Yung, A. R., Zhang, Y., Detweiler, A. M., Mekonen, H., Neff, N. F., Sit, R. V., Tan, M., Yan, J., Bean, G. R., Charu, V., Forgo, E., Martin, B. A., Ozawa, M. G., Silva, O., Toland, A., Vemuri, V. N., Afik, S., Awayan, K., Bierman, R., Botvinnik, O. B., Byrne, A., Chen, M., Dehghannasiri, R., Gayoso, A., Granados, A. A., Li, Q., Mahmoudabadi, G., McGeever, A., Olivieri, J. E., Park, M., Ravikumar, N., Stanley, G., Tan, W., Tarashansky, A. J., Vanheusden, R., Wang, P., Wang, S., Xing, G., Xu, C., Yosef, N., Culver, R., Dethlefsen, L., Ho, P., Liu, S., Maltzman, J. S., Metzger, R. J., Sasagawa, K., Sinha, R., Song, H., Wang, B., Artandi, S. E., Beachy, P. A., Clarke, M. F., Giudice, L. C., Huang, F. W., Huang, K. C., Idoyaga, J., Kim, S. K., Kuo, C. S., Nguyen, P., Rando, T. A., Red-Horse, K., Reiter, J., Relman, D. A., Sonnenburg, J. L., Wu, A., Wu, S. M., Wyss-Coray, T. 2022

    Abstract

    Cell-free RNA from liquid biopsies can be analyzed to determine disease tissue of origin. We extend this concept to identify cell types of origin using the Tabula Sapiens transcriptomic cell atlas as well as individual tissue transcriptomic cell atlases in combination with the Human Protein Atlas RNA consensus dataset. We define cell type signature scores, which allow the inference of cell types that contribute to cell-free RNA for a variety of diseases.

    View details for DOI 10.1038/s41587-021-01188-9

    View details for PubMedID 35132263

  • Increased double-negative alpha beta plus T cells reveal adult-onset autoimmune lymphoproliferative syndrome in a patient with IgG4-related disease HAEMATOLOGICA Brar, N., Spinner, M. A., Baker, M. C., Advani, R. H., Natkunam, Y., Lewis, D. B., Silva, O. 2022; 107 (1): 347-350
  • Case Report: Mature Plasmacytoid Dendritic Cell Proliferation Associated With a Lymphoid Neoplasm. Frontiers in oncology Fei, F., Liedtke, M., Silva, O. 2022; 12: 903113

    Abstract

    Mature plasmacytoid dendritic cell proliferations (MPDCPs) are clonal, non-malignant pDC proliferations that have been reported to occur in association with myeloid neoplasms such as CMML, AML (pDC-AML), and, rarely, MDS or MPNs. Here we report the first case of a MPDCP associated with T-lymphoblastic leukemia (T-ALL), a lymphoid neoplasm. The MPDCP in this case involved ~50% of the bone marrow, was found in nodular aggregates, expressed CD123, CD4, and CD303, and lacked CD56 and TCL1 expression. In addition, the MPDCP lacked CD34 and TdT but showed aberrant expression of CD7, CD5, CD10, and CD13, markers expressed by the abnormal T-lymphoblastic cells. Mutational analysis demonstrated mutations in JAK3, NOTCH1, NRAS, KRAS, DNMT3A, and SH2B3 but no mutations in TET2, ASLX1 or ZRSR2. Analysis of the pDC frequency in a separate cohort of T-ALL and control patients demonstrated that bone marrow pDCs are often decreased in patients with T-ALL compared to controls. This is the first report of a MPDCP associated with a lymphoid neoplasm and provides further support that MPDCP can arise from a multipotent hematopoietic progenitor with lymphoid and dendritic cell potential.

    View details for DOI 10.3389/fonc.2022.903113

    View details for PubMedID 35875095

  • RNA splicing programs define tissue compartments and cell types at single cell resolution. eLife Olivieri, J. E., Dehghannasiri, R., Wang, P. L., Jang, S., de Morree, A., Tan, S. Y., Ming, J., Ruohao Wu, A., Tabula Sapiens Consortium, Quake, S. R., Krasnow, M. A., Salzman, J. 2021; 10

    Abstract

    The extent splicing is regulated at single-cell resolution has remained controversial due to both available data and methods to interpret it. We apply the SpliZ, a new statistical approach, to detect cell-type-specific splicing in >110K cells from 12 human tissues. Using 10x data for discovery, 9.1% of genes with computable SpliZ scores are cell-type-specifically spliced, including ubiquitously expressed genes MYL6 and RPS24. These results are validated with RNA FISH, single-cell PCR, and Smart-seq2. SpliZ analysis reveals 170 genes with regulated splicing during human spermatogenesis, including examples conserved in mouse and mouse lemur. The SpliZ allows model-based identification of subpopulations indistinguishable based on gene expression, illustrated by subpopulation-specific splicing of classical monocytes involving an ultraconserved exon in SAT1. Together, this analysis of differential splicing across multiple organs establishes that splicing is regulated cell-type-specifically.

    View details for DOI 10.7554/eLife.70692

    View details for PubMedID 34515025

  • The RNA-binding protein IGF2BP3 is critical for MLL-AF4-mediated leukemogenesis. Leukemia Tran, T. M., Philipp, J., Bassi, J. S., Nibber, N., Draper, J. M., Lin, T. L., Palanichamy, J. K., Jaiswal, A. K., Silva, O., Paing, M., King, J., Katzman, S., Sanford, J. R., Rao, D. S. 2021

    Abstract

    Despite recent advances in therapeutic approaches, patients with MLL-rearranged leukemia still have poor outcomes. Here, we find that the RNA-binding protein IGF2BP3, which is overexpressed in MLL-translocated leukemia, strongly amplifies MLL-Af4-mediated leukemogenesis. Deletion of Igf2bp3 significantly increases the survival of mice with MLL-Af4-driven leukemia and greatly attenuates disease, with a minimal impact on baseline hematopoiesis. At the cellular level, MLL-Af4 leukemia-initiating cells require Igf2bp3 for their function in leukemogenesis. At the molecular level, IGF2BP3 regulates a complex posttranscriptional operon governing leukemia cell survival and proliferation. IGF2BP3-targeted mRNA transcripts include important MLL-Af4-induced genes, such as those in the Hoxa locus, and the Ras signaling pathway. Targeting of transcripts by IGF2BP3 regulates both steady-state mRNA levels and, unexpectedly, pre-mRNA splicing. Together, our findings show that IGF2BP3 represents an attractive therapeutic target in this disease, providing important insights into mechanisms of posttranscriptional regulation in leukemia.

    View details for DOI 10.1038/s41375-021-01346-7

    View details for PubMedID 34321607

  • Polytypic T-cell prolymphocytic leukemia. Blood Ames, E., Silva, O. 2021; 137 (15): 2125

    View details for DOI 10.1182/blood.2021010694

    View details for PubMedID 33856441

  • Classic Hodgkin lymphoma in Guatemalan children of age less than six years: analysis of immune regulatory pathways and the tumor microenvironment. Leukemia & lymphoma Silva, O., Charu, V., Ewalt, M. D., Metcalf, R. A., Zhao, S., Castellanos, E. M., Orellana, E., Natkunam, Y., Luna-Fineman, S. 2021: 1–13

    Abstract

    Classic Hodgkin lymphoma (cHL) in young children (ages 0-6) is rare in high income countries (HICs) but is more prevalent in low- and middle-income countries (LMICs) like Guatemala. Given that the majority of cHL studies have evaluated adolescent/adults, and the immune system changes with age, we sought to characterize Epstein-Barr virus (EBV) expression, immune regulatory pathway markers and the tumor microenvironment in 42 children ages 0-6 with cHL from Guatemala. We found a very high frequency of EBV expression (97.5%). Hodgkin cells showed increased expression of PD1 ligands and CD137, indicative of shared immune regulatory mechanisms with adult cHL. Pediatric cHL also showed an increase in CD8+ tumor infiltrating lymphocytes and tumor associated macrophages within the tumor microenvironment. Despite 25 having high risk disease, only 4 patients died from progressive disease, relapse or infection.

    View details for DOI 10.1080/10428194.2021.1885666

    View details for PubMedID 33627023

  • Nonleukemic T/B mixed phenotype acute leukemia with PHF6 and NOTCH1 mutations. Blood Silva, O., Kurzer, J. 2021; 138 (9): 818

    View details for DOI 10.1182/blood.2021012538

    View details for PubMedID 34473233

  • Chronic lymphoproliferative disorder of NK cells with TNFAIP3 and DNMT3A mutations. Blood Bulterys, P. L., Silva, O. 2021; 137 (24): 3460

    View details for DOI 10.1182/blood.2021011812

    View details for PubMedID 34137843

  • Additional considerations related to the elusive boundaries of EBV-associated T/NK-cell lymphoproliferative disorders. Haematologica Fernandez-Pol, S., Silva, O., Natkunam, Y. 2019; 104 (3): e125–e126

    View details for PubMedID 30819837

  • Defining the elusive boundaries of chronic active Epstein-Barr virus infection. Haematologica Fernandez-Pol, S., Silva, O., Natkunam, Y. 2018; 103 (6): 924–27

    View details for PubMedID 29866887

  • A Feedback-Based Training Module Improves Tumor Cellularity Estimation for Molecular Testing Weiel, J. J., Silva, O., Mooney, K. L., Lin, C., Kunder, C. A. NATURE PUBLISHING GROUP. 2017: 144A
  • Discs Large Homolog 1 Splice Variants Regulate p38-Dependent and -Independent Effector Functions in CD8+T Cells PLOS ONE Silva, O., Crocetti, J., Humphries, L. A., Burkhardt, J. K., Miceli, M. C. 2015; 10 (7)

    Abstract

    Functionally diverse CD8+ T cells develop in response to antigenic stimulation with differing capacities to couple TCR engagement to downstream signals and functions. However, mechanisms of diversifying TCR signaling are largely uncharacterized. Here we identified two alternative splice variants of scaffold protein Dlg1, Dlg1AB and Dlg1B, that diversify signaling to regulate p38-dependent and -independent effector functions in CD8+ T cells. Dlg1AB, but not Dlg1B associated with Lck, coupling TCR stimulation to p38 activation and proinflammatory cytokine production. Conversely, both Dlg1AB and Dlg1B mediated p38-independent degranulation. Degranulation depended on a Dlg1 fragment containing an intact Dlg1SH3-domain and required the SH3-ligand WASp. Further, Dlg1 controlled WASp activation by promoting TCR-triggered conformational opening of WASp. Collectively, our data support a model where Dlg1 regulates p38-dependent proinflammatory cytokine production and p38-independent cytotoxic granule release through the utilization of alternative splice variants, providing a mechanism whereby TCR engagement couples downstream signals to unique effector functions in CD8+ T cells.

    View details for DOI 10.1371/journal.pone.0133353

    View details for Web of Science ID 000358198700128

    View details for PubMedID 26186728

  • Selective Phosphorylation of the Dlg1AB Variant Is Critical for TCR-Induced p38 Activation and Induction of Proinflammatory Cytokines in CD8(+) T Cells JOURNAL OF IMMUNOLOGY Crocetti, J., Silva, O., Humphries, L. A., Tibbs, M. D., Miceli, M. C. 2014; 193 (6): 2651-2660

    Abstract

    CD8(+) T cells respond to TCR stimulation by producing proinflammatory cytokines, and destroying infected or malignant cells through the production and release of cytotoxic granules. Scaffold protein Discs large homolog 1 (Dlg1) specifies TCR-dependent functions by channeling proximal signals toward the activation of p38-dependent proinflammatory cytokine gene expression and/or p38-independent cytotoxic granule release. Two Dlg1 variants are expressed in CD8(+) T cells via alternative splicing, Dlg1AB and Dlg1B, which have differing abilities coordinate TCR-dependent functions. Although both variants facilitate p38-independent cytotoxicity, only Dlg1AB coordinates p38-dependent proinflammatory cytokine expression. In this study, we identify TCR-induced Dlg1 tyrosine phosphorylation as a key regulatory step required for Dlg1AB-mediated p38-dependent functions, including proinflammatory cytokine expression. We find that Dlg1AB but not Dlg1B is tyrosine phosphorylated by proximal tyrosine kinase Lck in response to TCR stimulation. Furthermore, we identify Dlg1 tyrosine 222 (Y222) as a major site of Dlg1 phosphorylation required for TCR-triggered p38 activation and NFAT-dependent expression of proinflammatory cytokines, but not for p38-independent cytotoxicity. Taken together, our data support a model where TCR-induced phosphorylation of Dlg1 Y222 is a key point of control that endows Dlg1AB with the ability to coordinate p38 activation and proinflammatory cytokine production. We propose blocking Dlg1AB phosphorylation as a novel therapeutic target to specifically block proinflammatory cytokine production but not cytotoxicity.

    View details for DOI 10.4049/jimmunol.1401196

    View details for Web of Science ID 000341859700005

    View details for PubMedID 25098293

  • Dantrolene Enhances Antisense-Mediated Exon Skipping in Human and Mouse Models of Duchenne Muscular Dystrophy SCIENCE TRANSLATIONAL MEDICINE Kendall, G. C., Mokhonova, E. I., Moran, M., Sejbuk, N. E., Wang, D. W., Silva, O., Wang, R. T., Martinez, L., Lu, Q. L., Damoiseaux, R., Spencer, M. J., Nelson, S. F., Miceli, M. C. 2012; 4 (164)

    Abstract

    Duchenne muscular dystrophy (DMD) causes profound and progressive muscle weakness and loss, resulting in early death. DMD is usually caused by frameshifting deletions in the gene DMD, which leads to absence of dystrophin protein. Dystrophin binds to F-actin and components of the dystrophin-associated glycoprotein complex and protects the sarcolemma from contraction-induced injury. Antisense oligonucleotide-mediated exon skipping is a promising therapeutic approach aimed at restoring the DMD reading frame and allowing expression of an intact dystrophin glycoprotein complex. To date, low levels of dystrophin protein have been produced in humans by this method. We performed a small-molecule screen to identify existing drugs that enhance antisense-directed exon skipping. We found that dantrolene, currently used to treat malignant hyperthermia, potentiates antisense oligomer-guided exon skipping to increase exon skipping to restore the mRNA reading frame, the sarcolemmal dystrophin protein, and the dystrophin glycoprotein complex in skeletal muscles of mdx mice when delivered intramuscularly or intravenously. Further, dantrolene synergized with multiple weekly injections of antisense to increase muscle strength and reduce serum creatine kinase in mdx mice. Dantrolene similarly promoted antisense-mediated exon skipping in reprogrammed myotubes from DMD patients. Ryanodine and Rycal S107, which, like dantrolene, targets the ryanodine receptor, also promoted antisense-driven exon skipping, implicating the ryanodine receptor as the critical molecular target.

    View details for DOI 10.1126/scitranslmed.3005054

    View details for Web of Science ID 000312393900004

    View details for PubMedID 23241744

  • Characterization of In Vivo Dlg1 Deletion on T Cell Development and Function PLOS ONE Humphries, L. A., Shaffer, M. H., Sacirbegovic, F., Tomassian, T., McMahon, K., Humbert, P. O., Silva, O., Round, J. L., Takamiya, K., Huganir, R. L., Burkhardt, J. K., Russell, S. M., Miceli, M. C. 2012; 7 (9)

    Abstract

    The polarized reorganization of the T cell membrane and intracellular signaling molecules in response to T cell receptor (TCR) engagement has been implicated in the modulation of T cell development and effector responses. In siRNA-based studies Dlg1, a MAGUK scaffold protein and member of the Scribble polarity complex, has been shown to play a role in T cell polarity and TCR signal specificity, however the role of Dlg1 in T cell development and function in vivo remains unclear.Here we present the combined data from three independently-derived dlg1-knockout mouse models; two germline deficient knockouts and one conditional knockout. While defects were not observed in T cell development, TCR-induced early phospho-signaling, actin-mediated events, or proliferation in any of the models, the acute knockdown of Dlg1 in Jurkat T cells diminished accumulation of actin at the IS. Further, while Th1-type cytokine production appeared unaffected in T cells derived from mice with a dlg1 germline-deficiency, altered production of TCR-dependent Th1 and Th2-type cytokines was observed in T cells derived from mice with a conditional loss of dlg1 expression and T cells with acute Dlg1 suppression, suggesting a differential requirement for Dlg1 activity in signaling events leading to Th1 versus Th2 cytokine induction. The observed inconsistencies between these and other knockout models and siRNA strategies suggest that 1) compensatory upregulation of alternate gene(s) may be masking a role for dlg1 in controlling TCR-mediated events in dlg1 deficient mice and 2) the developmental stage during which dlg1 ablation begins may control the degree to which compensatory events occur.These findings provide a potential explanation for the discrepancies observed in various studies using different dlg1-deficient T cell models and underscore the importance of acute dlg1 ablation to avoid the upregulation of compensatory mechanisms for future functional studies of the Dlg1 protein.

    View details for DOI 10.1371/journal.pone.0045276

    View details for Web of Science ID 000311313900112

    View details for PubMedID 23028902

  • Caveolin-1 Orchestrates TCR Synaptic Polarity, Signal Specificity, and Function in CD8 T Cells JOURNAL OF IMMUNOLOGY Tomassian, T., Humphries, L. A., Liu, S. D., Silva, O., Brooks, D. G., Miceli, M. C. 2011; 187 (6): 2993-3002

    Abstract

    TCR engagement triggers the polarized recruitment of membrane, actin, and transducer assemblies within the T cell-APC contact that amplify and specify signaling cascades and T effector activity. We report that caveolin-1, a scaffold that regulates polarity and signaling in nonlymphoid cells, is required for optimal TCR-induced actin polymerization, synaptic membrane raft polarity, and function in CD8, but not CD4, T cells. In CD8(+) T cells, caveolin-1 ablation selectively impaired TCR-induced NFAT-dependent NFATc1 and cytokine gene expression, whereas caveolin-1 re-expression promoted NFATc1 gene expression. Alternatively, caveolin-1 ablation did not affect TCR-induced NF-κB-dependent Iκbα expression. Cav-1(-/-) mice did not efficiently promote CD8 immunity to lymphocytic choriomeningitis virus, nor did cav-1(-/-) OT-1(+) CD8(+) T cells efficiently respond to Listeria monocytogenes-OVA after transfer into wild-type hosts. Therefore, caveolin-1 is a T cell-intrinsic orchestrator of TCR-mediated membrane polarity and signal specificity selectively employed by CD8 T cells to customize TCR responsiveness.

    View details for DOI 10.4049/jimmunol.1101447

    View details for Web of Science ID 000295034200018

    View details for PubMedID 21849673