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Epstein-Barr virus (EBV) is associated with hematologic and solid tumors. In this study, we utilized a hybridization capture-based next generation sequencing (NGS) platform that targets 400 genes associated with hematological malignancies to detect and quantify non-targeted viral-derived EBV reads that aligned to the EBV reference contig (NC_007605). We evaluated 5,234 samples from 3,636 unique patients with hematological neoplasms and found that 100 samples (1.9%) in 93 unique patients had ≥ 6 EBV reads (range, 6-32,325; mean, 827.5; median, 54). The majority (n=73, 73%) represented known EBV-associated conditions, and the most common was post-transplant lymphoproliferative disorders (n=21, 29%). Documented EBV viremia accounted for a moderate quantity of EBV reads in 4/27 samples corresponding to conditions not known to be EBV-associated, while suspected viremia or low-level activation was likely the etiology in the remaining 23 samples. A good correlation (Spearman r=0.8, 95% CI 0.74-0.85) was found between EBV reads by NGS and systematic semi-quantitative EBER ISH assessment in 162 available samples, particularly at higher level of EBV-involvement. An optimal threshold for significant morphologic EBV-involvement was found to be ≥10 reads by the receiver operating characteristic (ROC) analysis (AUC 0.990 and 95% CI 0.9974-1.000%). Thus, in addition to mutational analysis, hybrid-capture-based NGS panels can be used to detect and quantitate off-target EBV-derived viral DNA, which correlates well with morphology.

Tracheobronchial masses encompass a broad spectrum of entities, ranging from benign and malignant neoplasms to infectious and inflammatory processes. This article reviews the cross-sectional findings of tracheal tumors and tumor-like entities, correlates imaging findings with histologic pathology, and discusses pearls and pitfalls in accurately diagnosing and classifying tracheal tumors and mimics.

Monomorphic posttransplant lymphoproliferative disorders have been defined as lymphoid or plasmacytic proliferations that fulfill criteria for one of the B-cell or T/NK-cell neoplasms recognized in immunocompetent hosts in the current WHO Classification. Low-grade B-cell neoplasms have historically been excluded from this category, although rare reports of marginal zone lymphoma (MZL) have been described. We report 9 cases of posttransplant Epstein-Barr virus-negative MZL, all arising in solid organ transplant recipients (4 renal, 3 liver, 1 cardiac, and 1 liver, pancreas, and small bowel). Seven were extranodal MZL of mucosa-associated lymphoid tissue type, all of which had gastrointestinal involvement (4 colon, 1 duodenum, 1 stomach, and 1 oropharynx/base of tongue). Notably, the preferential involvement of intestine distinguishes posttransplant extranodal MZL from sporadic cases. Immunoglobulin light-chain restriction was seen in all cases, with polymerase chain reaction showing a monoclonal pattern in 7 of 8 cases with successful amplification of polymerase chain reaction products. A clonally unrelated recurrence was seen in one case. Next-generation sequencing identified recurrent mutations previously reported in MZL in 3/5 cases. MZL was diagnosed at least 1 year after solid organ transplant (median time to presentation, 84 mo; range, 13 to 108 mo). The median age was 44 (range, 9 to 73 y); the male: female ratio was 5:4. The mean follow-up was 33.4 months, with an indolent clinical course observed. A subset responded to reduction in immunosuppression and anti-CD20 therapy alone. These data support the designation of Epstein-Barr virus-negative MZL as an uncommon form of monomorphic posttransplant lymphoproliferative disorders.

Pediatric large B-cell lymphomas (LBCLs) share morphological and phenotypic features with adult types but have better prognosis. The higher frequency of some subtypes such as LBCL with IRF4 rearrangement (LBCL-IRF4) in children suggests that some age-related biological differences may exist. To characterize the genetic and molecular heterogeneity of these tumors, we studied 31 diffuse LBCLs (DLBCLs), not otherwise specified (NOS); 20 LBCL-IRF4 cases; and 12 cases of high-grade B-cell lymphoma (HGBCL), NOS in patients ≤25 years using an integrated approach, including targeted gene sequencing, copy-number arrays, and gene expression profiling. Each subgroup displayed different molecular profiles. LBCL-IRF4 had frequent mutations in IRF4 and NF-κB pathway genes (CARD11, CD79B, and MYD88), losses of 17p13 and gains of chromosome 7, 11q12.3-q25, whereas DLBCL, NOS was predominantly of germinal center B-cell (GCB) subtype and carried gene mutations similar to the adult counterpart (eg, SOCS1 and KMT2D), gains of 2p16/REL, and losses of 19p13/CD70. A subset of HGBCL, NOS displayed recurrent alterations of Burkitt lymphoma–related genes such as MYC, ID3, and DDX3X and homozygous deletions of 9p21/CDKN2A, whereas other cases were genetically closer to GCB DLBCL. Factors related to unfavorable outcome were age >18 years; activated B-cell (ABC) DLBCL profile, HGBCL, NOS, high genetic complexity, 1q21-q44 gains, 2p16/REL gains/amplifications, 19p13/CD70 homozygous deletions, and TP53 and MYC mutations. In conclusion, these findings further unravel the molecular heterogeneity of pediatric and young adult LBCL, improve the classification of this group of tumors, and provide new parameters for risk stratification.

Signaling through immune checkpoint receptors may lead to T-cell exhaustion and function as immune escape mechanisms in cancer. For diffuse large B-cell lymphoma (DLBCL), the mechanistic and prognostic importance of these markers on tumor cells and the tumor microenvironment remains unclear. We determined the immunohistochemical expression of PD-1, PD-L1, TIM-3, and LAG-3 on tumor cells and on tumor infiltrating lymphocytes (TILs) among 123 DLBCL patients. TIM-3 showed positive staining on tumor cells in 39% of DLBCL cases and PD-L1 expression was noted in 15% of cases. Both PD-1 and LAG-3 were positive on tumor cells in a minority of DLBCL cases (8.3% and 7.5%, respectively), but were more widely expressed on TILs in a correlated manner. With median follow-up of 44 months (n = 70, range 5-85), 4-year progression-free survival (PFS) and overall survival (OS) rates were significantly inferior among DLBCL patients with high vs low/negative TIM-3 expression (PFS: 23% [95% CI 7% to 46%] vs 60% [95% CI 43% to 74%], respectively, P = 0.008; OS: 30% [95% CI 10% to 53%] vs 74% [95% CI 58% to 85%], respectively, P = 0.006). Differences in OS remained significant when controlling for International Prognostic Index in Cox regression analyses (HR 3.49 [95% CI 1.40-6.15], P = 0.007). In addition, we observed that co-culture of DLBCL cell lines with primed T cells in the presence of anti-LAG-3 and anti-TIM-3 induced potent dose-dependent increases in in vitro cell death via AcellaTox and IL-2 ELISA assays, suggesting potent anti-tumor activity of these compounds.

Background Phenotypic characterization of immune cells in the bone marrow (BM) of patients with acute myeloid leukemia (AML) is lacking. Methods T‐cell infiltration was quantified on BM biopsies from 13 patients with AML, and flow cytometry was performed on BM aspirates (BMAs) from 107 patients with AML who received treatment at The University of Texas MD Anderson Cancer Center. The authors evaluated the expression of inhibitory receptors (programmed cell death protein 1 [PD1], cytotoxic T‐lymphocyte antigen 4 [CTLA4], lymphocyte‐activation gene 3 [LAG3], T‐cell immunoglobulin and mucin‐domain containing‐3 [TIM3]) and stimulatory receptors (glucocorticoid‐induced tumor necrosis factor receptor‐related protein [GITR], OX40, 41BB [a type 2 transmembrane glycoprotein receptor], inducible T‐cell costimulatory [ICOS]) on T‐cell subsets and the expression of their ligands (41BBL, B7‐1, B7‐2, ICOSL, PD‐L1, PD‐L2, and OX40L) on AML blasts. Expression of these markers was correlated with patient age, karyotype, baseline next‐generation sequencing for 28 myeloid‐associated genes (including P53), and DNA methylation proteins (DNA methyltransferase 3α, isocitrate dehydrogenase 1[IDH1], IDH2, Tet methylcytosine dioxygenase 2 [TET2], and Fms‐related tyrosine kinase 3 [FLT3]). Results On histochemistry evaluation, the T‐cell population in BM appeared to be preserved in patients who had AML compared with healthy donors. The proportion of T‐regulatory cells (Tregs) in BMAs was higher in patients with AML than in healthy donors. PD1‐positive/OX40‐positive T cells were more frequent in AML BMAs, and a higher frequency of PD1‐positive/cluster of differentiation 8 (CD8)‐positive T cells coexpressed TIM3 or LAG3. PD1‐positive/CD8‐positive T cells were more frequent in BMAs from patients who had multiply relapsed AML than in BMAs from those who had first relapsed or newly diagnosed AML. Blasts in BMAs from patients who had TP53‐mutated AML were more frequently positive for PD‐L1. Conclusions The preserved T‐cell population, the increased frequency of regulatory T cells, and the expression of targetable immune receptors in AML BMAs suggest a role for T‐cell–harnessing therapies in AML., T‐cell subsets are preserved in the bone marrow of patients with acute myeloid leukemia. The expression of targetable immune checkpoints by T cells suggests that therapies harnessing T cells may benefit these patients.

TO THE EDITOR: GATA2 encodes a zinc-finger transcription factor that is required for proliferation and survival of hematopoietic stem cells.[1][1] First described in 2011, germline heterozygous mutations in GATA2 lead to haploinsufficiency[2][2] and are associated with bone marrow failure

INTRODUCTION Mixed phenotype (MP) is characteristic for de novo mixed phenotype acute leukemia (dnMPAL) but can also be seen in blast phase of myeloproliferative neoplasms (MPN-BP), myeloid/lymphoid neoplasms with eosinophilia & rearrangements, acute myeloid leukemia (AML) with recurrent cytogenetic abnormalities (AML-RCA) and secondary AML (sAML) including AML with myelodysplasia-related changes (AML-MRC) and therapy-related AML (t-AML). Although WHO classification excludes sAML with MP (sAML-MP) from dnMPAL, the significance of MP in the setting of sAML and their genetic landscape has not been studied. METHODS The MSKCC pathology data base was searched from 01/2014 to 09/2020 and a cohort of 125 patients with MP as defined per WHO 2016 classification was obtained. The clinical, morphologic, immunophenotypic, and cytogenetic/molecular results were reviewed. Patients with a diagnosis of AML-RCA, myeloid/lymphoid neoplasms with eosinophilia & rearrangements, MPN-BP, B-ALL with isolated MPO and myelodysplastic syndrome (MDS) were excluded (Fig 1). RESULTS 50 cases of sAML-MP (14 t-AML and 36 AML-MRC) were retrieved and compared to 42 dnMPAL cases and 100 sAML without MP (37 t-AML and 63 AML-MRC) (Table 1). The median age at diagnosis was 66 years which was higher than dnMPALs (44.5 yrs, p value Molecular studies (Table 2) revealed that the most commonly mutated genes in sAML-MP were RUNX1, DNMT3A, TP53 which were all present in a significantly higher frequency in comparison to dnMPAL. The frequency of RUNX1 mutation was higher in sAML-MP even in comparison to sAML without MP. Conversely, mutations in PHF6 frequently noted in dnMPALs were uncommon in sAML cohorts. Cluster analysis based on immunophenotyping of the 3 cohorts revealed 6 clusters (Fig 2) with separation between the 3 cohorts. Most of the dnMPAL with B/M phenotype formed a distinct tight cluster (cluster 3). Most of the sAML-MP were seen clustering together in cluster 4 whereas sAML without MP predominated in cluster 5 and 6. Cluster 1 revealed a mixture of dnMPAL and sAML-MP with predominantly T/M phenotype. The overall survival (OS) was inferior in the sAML-MP cohort in comparison to dnMPAL cohort (median survival: 6.77 vs 36.99 mths, p value 0.00005; Fig 3A) and was similar to the sAML without MP cohort (median survival: 6.77 vs 4.96 mths, p value 0.33; Fig 3A). In a multivariate analysis, model adjusted for the age and allotransplant did not explain difference in OS between these groups. Comparison of OS between the 6 clusters (Fig 3B) revealed better OS in clusters 2 and 3 that were enriched for dnMPAL. Cluster1 in spite of having a mixture of dnMPAL and sAML-MP did poorly. This could be driven by enrichment in DNMT3A mutations in the dnMPAL with T/M phenotype. Immunophenotypically distinct blast populations were flow cytometrically sorted in 4 cases of sAML-MP (2 each with T/M and B/M phenotype). While the majority of the genetic abnormalities were shared between populations with different lineages, a case with multiple mutations showed divergent KRAS/NRAS mutations showing clonal divergence as possible late event driving distinct lineage maturation (Table 3). CONCLUSION sAML-MP and sAML without MP are clinically similar and have biological overlaps with frequent somatic mutations in TP53, chromatin modifying genes and spliceosome-complex genes, which is different from dnMPAL. However, the frequency of RUNX1 mutation is higher in sAML-MP than sAML without MP suggesting its role in lineage infidelity. Though, cluster analysis based on immunophenotype separates the 3 cohorts into enriched clusters, there are still overlaps between sAML-MP and dnMPAL especially with a T/M phenotype as well as between sAML-MP and sAML without MP especially in TP53 mutated cases. Additional RNA seq and ATAC seq are currently being performed on flow cytometrically sorted distinct blast populations of the sAML-MP cases. Figure 1 Figure 1. Disclosures Galera: Paige.AI: Research Funding. Dogan: Physicians' Education Resource: Honoraria; Seattle Genetics: Consultancy; Takeda: Consultancy, Research Funding; EUSA Pharma: Consultancy; Roche: Consultancy, Research Funding; Peer View: Honoraria. Tallman: Syros: Membership on an entity's Board of Directors or advisory committees; NYU Grand Rounds: Honoraria; Kura: Membership on an entity's Board of Directors or advisory committees; Innate Pharma: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Biosight: Membership on an entity's Board of Directors or advisory committees; Roche: Membership on an entity's Board of Directors or advisory committees; Jazz Pharma: Membership on an entity's Board of Directors or advisory committees; Oncolyze: Membership on an entity's Board of Directors or advisory committees; KAHR: Membership on an entity's Board of Directors or advisory committees; Orsenix: Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Amgen: Research Funding; Rafael Pharmaceuticals: Research Funding; Glycomimetics: Research Funding; Biosight: Research Funding; Orsenix: Research Funding; Abbvie: Research Funding; Mayo Clinic: Honoraria; UC DAVIS: Honoraria; Northwell Grand Rounds: Honoraria; NYU Grand Rounds: Honoraria; Danbury Hospital Tumor Board: Honoraria; Acute Leukemia Forum: Honoraria; Miami Leukemia Symposium: Honoraria; New Orleans Cancer Symposium: Honoraria; ASH: Honoraria; NCCN: Honoraria. Levine: Celgene: Research Funding; Incyte: Consultancy; Roche: Honoraria, Research Funding; Morphosys: Consultancy; Imago: Membership on an entity's Board of Directors or advisory committees; Lilly: Honoraria; QIAGEN: Membership on an entity's Board of Directors or advisory committees; Astellas: Consultancy; Amgen: Honoraria; Gilead: Honoraria; Zentalis: Membership on an entity's Board of Directors or advisory committees; Ajax: Membership on an entity's Board of Directors or advisory committees; Prelude: Membership on an entity's Board of Directors or advisory committees; Isoplexis: Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy; C4 Therapeutics: Membership on an entity's Board of Directors or advisory committees; Mission Bio: Membership on an entity's Board of Directors or advisory committees; Auron: Membership on an entity's Board of Directors or advisory committees. Roshal: Physicians' Education Resource: Other: Provision of services; Celgene: Other: Provision of services; Auron Therapeutics: Other: Ownership / Equity interests; Provision of services. Glass: GLG: Consultancy. Xiao: Stemline Therapeutics: Research Funding.

INTRODUCTION Lymphoma cells are dependent on the tumor microenvironment (TME) for their survival and proliferation. Dissection of TME composition provides insight into lymphomagenesis, better prognostication, and enhancement of therapeutic options. Flow cytometry provides a robust approach for single-cell analysis. Nonetheless lack of well-defined comparator groups and/or a robust, reproducible approaches for analyzing the multidimensional data often limited such studies. In the current study, we analyzed the T cell background on a large reference set of follicular hyperplasia (FH) lymph node samples utilizing a robust standardized high dimensionality flow cytometry and a novel reproducible analytical pipeline. We then compared this baseline reference set with tumor infiltrating T cell subsets in follicular lymphoma (FL; in treatment naïve FL-NA and relapsed/refractory FL-RR sets). METHODS On behalf of the imCORE Network we analyzed 44 FH and 81 FL (35 FL-NA and 44 FL-RR) with 2 standardized flow cytometry panels (23 antigen/18-color) (Table 1). We evaluated the T cell subset distribution as well as immune checkpoint expression (TIGIT, TIM3, PD-1, CD96, LAG3, CTLA4, CD73) within analytically defined T cell clusters. Analysis was performed using semiautomated multi-step analytical pipeline as outlined in Figure 1. Using standardized instrument settings and an R-based algorithms (gaussNorm) to minimize technical variations in sample acquisition we analyzed the T-cells subpopulations using a dimensionality reduction technique (UMAP), combined with an unsupervised clustering algorithm (FlowSOM). Statistical analysis was performed using non-parametric Wilcoxon test. RESULTS In the 3 cohorts, several marked differences in the composition T cells subsets were observed. Compared to FH the FL lymph nodes were depleted for CD4 & CD8 naïve subsets (Table 2) and were characterized by an immune suppressive microenvironment enriched in specific subsets of activated T regulatory cells and exhausted memory effector cells. The pool of CD8 naïve cells was restored in FL-RR cases (Table 2). FL-NA nodes showed enrichment of T follicular regulatory cells (Tfr; Table 2) (0.9% vs 2.7%, p In association with the increase of Tfr cells, the concentration of CTLA4+, TIGIT+, PD1bright T follicular helper cells (Tfh) was reduced in FL-RR compared to FL-NA (Fig. 2C). The Tfr/Treg expansion was also associated with a marked increase in exhausted memory T cells in both CD4 and CD8 compartments (CD4 EM TP and CD8 EM DP, Table 2). In FL isolates the CD4 compartment was characterized by the expression of triple positive (CTLA4, TIGIT, PD1) phenotype in EM cells while the memory CD8 cells overexpressed TIGIT and PD1 (Fig. 2D). A smaller subpopulation of memory CD8 cells, almost undetectable in FH samples, characterized by the expression of CTLA4, PD1, TIGIT and TIM3 is expanded in FL isolates (Fig. 2D). CONCLUSION Our data suggest that change in balance between TFH and Tfr may lead to more aggressive therapy resistant disease in FL. The interplay between TFH and Tfr, has been postulated to shape the immune response in FL with TFH promoting germinal center formation and Tfr inhibiting TFH and follicular effector T cells. While both TFH and Tfr compartments are expanded in FL, in the relapsed/ refractory FL cases, the Tfr compartment is further expanded at the expense of TFH leading to more immunosuppressive background. Furthermore our study suggests a rational way of designing immune checkpoint inhibitor studies in FL. Effector memory T-cells in FL isolates show an exhausted phenotype characterized by the expression of the inhibitory receptors CTLA4, TIGIT, PD1 in the CD4 compartment, and TIGIT, PD1 in the CD8. In addition, the noteworthy expansion of TIM3+ memory CD8 cells in FL. Targeting these most highly expressed checkpoints in FL alone or in combination may provide an avenue for rational trial design. Figure 1 Figure 1. Disclosures Roshal: Celgene: Other: Provision of services; Auron Therapeutics: Other: Ownership / Equity interests; Provision of services; Physicians' Education Resource: Other: Provision of services. Dogan: Physicians' Education Resource: Honoraria; Peer View: Honoraria; Roche: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Seattle Genetics: Consultancy; EUSA Pharma: Consultancy.

Advances in molecular genetic sequencing techniques have contributed to the elucidation of previously unknown germline mutations responsible for inherited thrombocytopenia (IT). Regardless of age of presentation and severity of symptoms related to thrombocytopenia and/or platelet dysfunction, a subset of patients with IT are at increased risk of developing myeloid neoplasms during their life time, particularly those with germline autosomal dominant mutations in RUNX1, ANKRD26, and ETV6. Patients may present with isolated thrombocytopenia and megakaryocytic dysmorphia or atypia on baseline bone marrow evaluation, without constituting myelodysplasia (MDS). Bone marrow features may overlap with idiopathic thrombocytopenic purpura (ITP) or sporadic MDS leading to misdiagnosis. Progression to myelodysplastic syndrome/ acute myeloid leukemia (MDS/AML) may be accompanied by progressive bi- or pancytopenia, multilineage dysplasia, increased blasts, cytogenetic abnormalities, acquisition of bi-allelic mutations in the underlying gene with germline mutation, or additional somatic mutations in genes associated with myeloid malignancy. A subset of patients may present with MDS/AML at a young age, underscoring the growing concern for evaluating young patients with MDS/AML for germline mutations predisposing to myeloid neoplasm. Early recognition of germline mutation and predisposition to myeloid malignancy permits appropriate treatment, adequate monitoring for disease progression, proper donor selection for hematopoietic stem cell transplantation, as well as genetic counseling of the affected patients and their family members. Herein, we describe the clinical and diagnostic features of IT with germline mutations predisposing to myeloid neoplasms focusing on mutations involving RUNX1, ANKRD26, and ETV6.

Immunophenotyping by multiparameter flow cytometry is a rapid and efficient technique to simultaneously assess and correlate multiple individual cell properties like size and internal complexity along with antigen expression in a population of cells. This method is utilized for rapid characterization of the blasts and classification of acute myeloid leukemia (AML), in both the peripheral blood (PB) and bone marrow (BM). This technique is not only useful in the initial diagnosis but also in monitoring and determining prognosis of the disease through minimal residual disease (MRD) testing. This chapter provides an overview of procedures for specimen processing, staining, and immunophenotyping of AML and describes the principles of data analysis for AML classification and MRD testing.

Therapeutic leukapheresis can control the white blood cell count (WBC) of pregnant women with chronic myelogenous leukemia (CML) who have hyperleukocytosis without leukostasis. The medical justification for this treatment has not been objectively documented. We report a 27-year-old woman, diagnosed with CML at 10-week gestation, who developed severe dyspnea on exertion. A workup that included chest CT and echocardiography with a bubble study detected no cardiopulmonary pathology to explain her symptoms, and thus she was referred for leukapheresis. Prior to her first leukapheresis, which lowered her WBC from 154 × 10(3) /μL to 133 × 10(3) /μL, her oxygen saturation (SpO2 ) on room air decreased from 98 to 93% during 100 feet of slow ambulation and she was dyspneic. Just after the leukapheresis, her dyspnea on exertion was much improved and her SpO2 remained at 98% with repeat ambulation. Spirometry and lung volume studies obtained before and after her first leukapheresis demonstrated 32 and 31% improvements in forced vital capacity and forced expiratory volume in 1 s respectively, a 25% increase in functional residual capacity, and a 142% improvement in expiratory reserve volume. Residual volume decreased by almost 20%. Three times in a week, leukapheresis was continued until her WBC was controlled with interferon α-2b approximately 4 weeks later. Her dyspnea had completely resolved. She gave birth by elective caesarean section to a healthy boy at 32 weeks. Corroboration of symptom relief by leukapheresis with physiological data may justify such treatment in pregnant patients with CML. J. Clin. Apheresis 31:393-397, 2016. © 2015 Wiley Periodicals, Inc.

Sirolimus is an immunosuppressant used to prevent graft versus host disease in allogeneic hematopoietic stem cell transplant recipients. It has a large volume of distribution (12 ± 7.5 l/kg) and within the intravascular space ∼95% of it is bound to red blood cells. Because of potential toxic effects at high trough levels, therapeutic drug monitoring is recommended for sirolimus. We present a case of severe hepatic dysfunction due to Hepatitis B and sirolimus toxicity, in a 51-year-old male stem cell transplant recipient. An automated red cell exchange decreased his blood sirolimus level from 22.6 to 10.3 ng/ml (55% reduction) and improved his liver enzymes. Re-equilibration of sirolimus from other compartments to the blood necessitated a series of four red cell exchanges, after which the sirolimus level was 4.7 ng/ml. Although the patient ultimately succumbed to multiorgan failure, red cell exchange may be considered for acute removal of sirolimus in selected patients. J. Clin. Apheresis, 2015. © 2015 Wiley Periodicals, Inc.

Background: Patient-derived tumor xenografts (PDX) are powerful tools to study cancer biology, cancer genomics and developmental therapeutics. A common problem in the development of PDX models is proliferation of atypical lymphocytes at the implantation site, which often overtake or limit the growth of the original tumor. This atypical lymphocyte proliferation has been described as XABLD in our PDX models. In this study, we characterized XABLD cases by morphology, immunophenotyping and genomic profiling. We hypothesize that XABLD tumors are morphologically and phenotypically similar to EBV-driven post-transplant lymphoproliferative disease (PTLD) and diffuse large B cell lymphoma (DLBCL). XABLD is a surrogate model to study EBV-driven PTLD and DLBCL. Materials and Methods: Models were generated from patient tissue collected under NCI Tissue Procurement Protocol (clinicaltrials.gov: NCT00900198) and CIRB Tissue Procurement Protocol 9846 for development of models for NCI’s Patient-Derived Models Repository (https://pdmr.cancer.gov). Specimens were implanted subcutaneously in NOD/SCID/IL2Rg null (NSG) mice and animal health was monitored throughout the study. Tumors in mice with suspected XABLD were harvested and reviewed by histology and immunohistochemical analysis for CD45, B and T cell markers, EBV status, B-cell clonality assay. All samples were also classified by the Lymph2Cx NanoString cell of origin assay and transcriptome profiling. Results: XABLD cases were found to originate from both solid tumor and circulating tumor cell implants. XABLD is a rapidly growing tumor positive for CD45, CD20, and LMP1 stains, 36 of 42 cases are strongly positive for PD-L1 stain. 39 of 42 cases exhibited an activated B cell (ABC) phenotype with evidence of elevated NF-kB signaling. Most cases were monoclonal for IGK/IGH and contained high numbers of tumor infiltrating CD8-positive T-cells with associated high mRNA expression of activated T cell markers. Conclusion: The clinical presentation, morphology and molecular characteristics of XABLD cases were similar to EBV-driven DLBCL. As the XABLD models exhibited frequent PD-L1 expression and marked infiltration of CD8-positive T cells, they may be useful for in vitro evaluation of checkpoint inhibitor response and T cell antitumor activity. Grant Support: This project has been funded in part with federal funds from the National Cancer Institute, National Institutes of Health, under Contract No. HHSN261200800001E. The content of this publication does not necessarily reflect the views or policies of the Department of Health and Human Services, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government. Citation Format: Tomas Vilimas, Gloryvee Rivera, Brandie Fullmer, Wiem Lassoued, Lindsay Dutko, Amanda Peach, Corinne Camalier, Li Chen, Rajesh Patidar, Suzanne Borgel, John Carter, Howard Stotler, Raymond Divelbiss, Jesse Stottlemyer, Michelle M. Gottholm-Ahalt, Michelle Crespo-Eugeni, Sean McDermott, William Jacob, Liqiang Xi, Pallavi Galera, Yvonne A. Evrard, Melinda G. Hollingshead, Elaine S. Jaffe, Mark Raffeld, Biswajit Das, Chris Karlovich, Vivekananda Datta, James H. Doroshow, P. Mickey Williams. Xenograft-associated B cell lymphoproliferative disease (XABLD) as a surrogate model to study Epstein-Barr virus (EBV) driven B cell Diseases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1056.

Background. While 2% of all extranodal Non-Hodgkin Lymphomas present in the thyroid, there exists insufficient data to describe the incidence of mantle cell lymphoma in the thyroid. A case series of 1400 patients revealed that Patient Findings. A 65-year-old female was referred for a multinodular goiter. Multiple fine needle aspirations from the dominant right nodule were consistent with Hashimoto’s thyroiditis and flow cytometry was negative. Due to progressing dysphagia, she underwent total thyroidectomy.Summary. Pathology revealed MCL with mantle zone growth pattern in the right thyroid. Flow cytometry showed monoclonal B cells comprising 9% of total cells. The Ki-67 index was 10%. She was diagnosed as having stage IIE MCL and offered conservative management by medical oncology, given that she had no B symptoms.Conclusion. Though chemotherapy is the treatment of choice in MCL, a subset of patients with low-grade disease may be observed. As in our patient, mantle zone growth pattern and a Ki-67 index < 10% suggest a favorable prognosis. A diagnosis of primary MCL in the thyroid remains rare and staging modalities as well as treatment options continue to evolve.

Background: In the United States and Europe, about 15-35% of head and neck squamous cell carcinoma are caused by human papillomavirus (HPV). The expression of p16 has been demonstrated to be a favorable biomarker for patients with head and neck squamous cell carcinoma. However, p16 expression and its prognostic value in laryngeal squamous cell carcinoma in Chinese patients are unknown. We aim to investigate p16 expression and its prognostic value in a large group of Chinese patients with laryngeal squamous cell carcinoma. Design: A total of 236 patients with laryngeal squamous cell carcinomas (laryngectomy, n=110; biopsy, n=126) obtained from the Surgical Pathology file (2000-2005), Cancer Center of SunYat-sen University, Guangzhou, People’s Republic of China were examined by immunohistochemistry for p16 expression. Overall survival was measured from the date of laryngectomy or biopsy to the date of death, and was censored from the date of last follow-up. Median follow-up period was 5 years and 3 months (63 months, range 7-123 months). Results: Clinical characteristics of the 236 patients with laryngeal squamous cell carcinoma showed that age, tumor stage and grade, and vital status (alive or dead) were not associated with p16 expression. Only 43 of 236 (18%) laryngeal squamous cell carcinomas expressed p16. Kaplan-Meier analysis showed that the 10-year overall survival rate was similar in patients with p16 positive tumors and patients with p16 negative tumors (31% vs. 34%; P=0.28; 95% confidence interval [CI], 0.34 to 1.37). Conclusion: The expression of p16 was found in only 18% Chinese patients with laryngeal squamous cell carcinomas. Unlike Caucasian patients, this large cohort study provides the first evidence that p16 positivity is not a favorable biomarker for patients with laryngeal squamous cell carcinomas in China.

Metaplastic breast carcinoma (MBC) is a heterogenous group of tumors that diverge from conventional glandular differentiation. The metaplastic component can be focal or may be present purely posing diagnostic challenges. Since MBC may show focal immunostaining or may even be negative for some cytokeratins (CK), different CKs are often needed to prove their epithelial origin. OSCAR is a relatively new broad-spectrum anti-CK antibody. Thirty MBC cases diagnosed at our institution were retrieved, including 7 spindle cell carcinomas. Representative slides were immunostained for CK-OSCAR, CK-AE1/AE3, CAM5.2, CK-903, and CK5/6. Nineteen spindle cell lesions were used as controls, including 6 malignant and 10 borderline phyllodes tumor, 1 inflammatory pseudotumor, 1 solitary fibrous tumor, and 1 nodular fasciitis case. All 30 cases (100%) of metaplastic carcinomas were positive for CK-OSCAR, compared with 27/30 (90%, P=0.076) for CK-AE1/AE3, 21/30 (70%, P≤0.01) for CK-903, 19/30 (63.3%, P≤0.01) for CAM5.2, and 15/30 (50%, P≤0.01) for CK5/6. All control cases were negative for CK-OSCAR. All 7 spindle cell carcinomas were also positive for CK-OSCAR (100%) compared with 6/7 (85.7%) for CK-AE1/AE3, 4/7 (57%) for CK-903, 3/7 (42.8%) for CAM5.2, and 2/7 (28.5%) for CK5/6. Our data show that CK-OSCAR is more sensitive than other individual CKs in diagnosing MBC. Coupled with high specificity, CK-OSCAR may potentially be used in lieu of a panel of CKs to identify the epithelial origin of these tumors, especially in spindle cell tumors. This is particularly useful in limited core biopsy specimens, to help guide treatment and simultaneously lower testing costs.

BACKGROUND Pediatric aggressive large B-cell lymphomas (LBCL) share morphological and phenotypic features with adult types but seem to have better prognosis. Additionally, a specific subtype carrying IRF4 translocations (LBCL-IRF4) has been recently identified in this age group. In adults, the cell-of-origin (COO) distinction of diffuse large B-cell lymphoma (DLBCL) based on gene expression signatures (germinal center B-cell like, GCB and activated B-cell like, ABC) and more recently clusters of genetic alterations have identified molecularly distinct DLBCL subsets that may benefit from novel therapeutic targets. The integration of pediatric population in these clinically relevant molecular subgroups and its clinical importance is not well known. The aim of this study was to characterize the molecular heterogeneity of LBCL in pediatric and young adult patients and evaluate their potential clinical impact. DESIGN Sixty-one LBCL diagnosed in patients ≤25 years-old (median age 14 years old, male/female 38/23) were included in the study. Molecular analyses included fluorescence in situ hybridization for MYC, BCL2, IRF4 and BCL6, copy number (CN) analysis (Oncoscan, Affymetrix), COO Lymph2Cx assay (NanoString) and targeted next generation sequencing of 96 B-cell lymphoma driver genes (SureSelect XT, Agilent Technologies). CNA and mutational profiles were compared to those previously published in adult DLBCL. Correlation of molecular features and event free survival (EFS) was performed using Kaplan-Meier curves. RESULTS Histologically, 33 were DLBCL, 20 LBCL-IRF4 and 8 high grade B-cell lymphomas, not otherwise specified (HGBCL). Nodal disease was present in 57%, mainly in the cervical region. COO distribution was: 68% GCB, 18% ABC and 13% unclassified. Most of LBCL-IRF4 cases were GCB-COO (73%). The IRF4 translocation was demonstrated in 16 out of 19 cases diagnosed as LBCL-IRF4 and an IGH rearrangement was seen in the other 3. Five cases carried MYC-breaks (3 DLBCL and 2 HGBCL) and two cases carried BCL6-breaks (1DLBCL and 1HGBCL). BCL2 rearrangements were absent. CN analysis detected alterations in 46/51 cases with recurrent gains (>15%) of 1q, 2p16, 11q, trisomies 7 and 12, and recurrent losses (>10%) of 1p36, 6q21-q22, 15q24, 17p13 and 19p13. Recurrent homozygous deletions were observed at 19p13/CD70 (6 cases), 9p13/CDKN2A (3 cases) and 13q14/RB1 (2 cases). Alteration patterns suggestive of chromothripsis were found in 10% (5/51) of the cases. No ABC-DLBCL related alterations such as 3p21-p14, 6q21-q25, 9p21.3 and 17p13 losses were seen. Targeted sequencing detected a total of 434 variants in 44 of 47 cases (mean 9.2 mutations/case). A pipeline for selection of driver mutations revealed a total of 270 mutations (62%) with potential functional effect. Recurrent mutations found in >15% of the cases affected IRF4, SOCS1, PIM1, CARD11, ACTB and CCND3 genes. In comparison to adult DLBCL, pediatric and young adult cases had significantly lower incidence of MYD88 (5 cases), CREBBP,TP53 (3 cases each) and TNFRSF14 (2 cases) mutations which are strongly associated with the definition of established mutational clusters in adult DLBCL. In our cohort, the morphological subtypes displayed different molecular profiles. IRF4 variants (some cases with >7 variants) and mutations in NF-kB pathway (CARD11, CD79B and MYD88-non L265P) were found specifically in the LBCL-IRF4 subgroup, whereas mutations in GCB related genes such as SOCS1 and EZH2 were particularly seen in cases with DLBCL diagnosis. All 49 patients with available follow-up received chemotherapy as first line treatment (41% containing Rituximab). Variables significantly associated with poor EFS in univariate analysis were age >18 years, ABC-COO, Stage IV, high genetic complexity (chromothripsis and/or >10 CN alterations), 2p16/REL gain/amplification, 9p21.3/CDKN2A homozygous deletions, MYC rearrangements and mutations in MYC, TP53 and DDX3X genes. CONCLUSION Despite pediatric/young-adult LBCL having overlapping features with adult disease our findings suggest that LBCL in young age have specific molecular mechanisms and highlight potential key drivers of these lymphomas in this age group. Disclosures No relevant conflicts of interest to declare.

Background: State of the art treatment for patients with NDMM involves induction with triplet-based regimens utilizing combinations of immunomodulatory drugs and proteasome inhibitors (PI) which improve time to progression (TTP), progression-free survival, and overall survival (OS) over doublet regimens. Carfilzomib is a selective PI with FDA approval in the KRd combination regimen for the treatment of patients with relapsed or refractory MM. Carfilzomib-based combinations are associated with increased clinical benefit over bortezomib-based combinations and carfilzomib does not cause neuropathy. This phase 2 study of 45 patients demonstrated that deep responses with KRd-r is achieved in the NDMM setting (Korde et al. JAMA Onc 2015). Here, we expand on our initial results in assessing response to present the long-term durability of minimal residual disease negativity (MRDneg) complete response (CR) and time to progression. We also characterize TTP by depth of response, age, and cytogenetic risk profile. Methods:Treatment-naïve patients with MM were treated for 8 cycles (28-day cycles) with carfilzomib 20/36 mg/m2 IV days 1, 2, 8, 9, 15, 16; lenalidomide 25 mg PO days 1-21, and dexamethasone 20/10 mg IV/PO days 1, 2, 8, 9, 15, 16, 22, 23. Transplant eligible patients underwent stem cell collection after ≥4 cycles and then continued KRd treatment (i.e. without default autologous stem cell transplant (ASCT)). After 8 cycles of KRd, patients received 2 years of lenalidomide 10 mg PO maintenance on days 1-21. The primary objective of the study was to estimate the rate of ≥ Grade 3 peripheral neuropathy with secondary objectives of International Myeloma Working Group criteria for overall response rate (ORR), MRDneg CR, TTP, and response duration (DoR) assessed after every cycle during induction and subsequently after every 90 days of maintenance therapy. Assessment of MRDneg CR by multi-color flow cytometry (bone marrow aspirate; 10-5 sensitivity) was performed after 8 cycles of induction, 1 and 2 years of lenalidomide maintenance, and then annually. Results: Forty-five patients meeting eligibility criteria were enrolled (60% male; 42% ≥ age 65, range 40-89; race: 82% White, 13% Black, 4% Asian; isotypes: 51% IgG kappa, 16% IgG lambda, 13% IgA kappa, 9% IgA lambda, 9% free kappa, and 4% free lambda; 33% high risk cytogenetics, del(17p), t(4;14), t(14;16)or t(14;20)). The median potential follow up was 5.7 years (68.3 months). The ORR was 97.8% (95% Confidence Interval (CI): 88.2-99.9%) with a median DoR of 65.7 months (95% CI: 55.6-not reached (NR) months). Strikingly, 28 of the 45 patients, 62.2%, (95% CI: 46.5-76.2%) attained deep responses of MRDneg CR; durability of MRDneg CR was observed up to at least 70 months with a median duration of over 4 years (52.4 months; 95% CI: 35.3-61.6 months). Moreover, the median TTP was over five and a half years (67.3 months; 95% CI: 51.0-NR months) and the median OS was NR, however, at 80 months, 84.3% of patients were still alive. As expected, patients who attained MRDneg CR, by cycle 8, had a 78% reduction in the risk of progression (Hazard Ratio (HR): 0.22 (95% CI: 0.07-0.69); p=0.005) (Figure 1). Importantly, these deep responses of MRDneg CR and long progression free durations were observed regardless of age group or cytogenetic-based risk profile (Table 1). Toxicities have been previously reported and were generally manageable with no Grade ≥ 3 neuropathy or death due to toxicity. Conclusions: Upfront treatment of NDMM with the modern and highly efficacious KRd-r regimen incorporating a "by-default-delayed" ASCT strategy led to high rates of MRDneg CR (10-5 sensitivity) which even more importantly were sustained with a median duration of over 4 years. Moreover, attaining MRDneg CR, was strongly associated with a delay in progression. Clinically important, we observed that these deep responses and long progression-free durations are observed regardless of age or cytogenetic risk and stress the importance of utilizing highly efficacious triplet-based regimens for these sub-categories of NDMM. Lastly, our results with KRd-r in NDMM compare favorably to ASCT-based regimens and question the use of upfront ASCT for all patients. Our observed median TTP of 67 months is approximately 17 months longer than published data using the regimen of bortezomib, lenalidomide, and dexamethasone with ASCT (Attal et al. NEJM 2017). Updated results will be presented at the Annual Meeting. Disclosures Korde: Amgen: Research Funding. Mailankody:Janssen: Research Funding; Juno: Research Funding; Takeda: Research Funding; Physician Education Resource: Honoraria. Landgren:Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Merck: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Consultancy; Pfizer: Consultancy; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Sirolimus is an immunosuppressant used to prevent graft versus host disease in allogeneic hematopoietic stem cell transplant recipients. It has a large volume of distribution (12 ± 7.5 l/kg) and within the intravascular space ∼95% of it is bound to red blood cells. Because of potential toxic effects at high trough levels, therapeutic drug monitoring is recommended for sirolimus. We present a case of severe hepatic dysfunction due to Hepatitis B and sirolimus toxicity, in a 51-year-old male stem cell transplant recipient. An automated red cell exchange decreased his blood sirolimus level from 22.6 to 10.3 ng/ml (55% reduction) and improved his liver enzymes. Re-equilibration of sirolimus from other compartments to the blood necessitated a series of four red cell exchanges, after which the sirolimus level was 4.7 ng/ml. Although the patient ultimately succumbed to multiorgan failure, red cell exchange may be considered for acute removal of sirolimus in selected patients.