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INTRODUCTION Coronavirus disease 2019 (COVID-19) is a respiratory disease caused by a novel coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Recent studies have suggested that COVID-19 positive patients present with leukopenia, lymphopenia, neutrophilia, thrombocytopenia, and higher neutrophil: lymphocyte ratio (NLR) and monocyte: lymphocyte ratio (MLR). More recently, we reported hypersegmented granulocytes and COVID-19 infection in Blood. 2020 Jun 11;135(24):2196. Neutrophil hypersegmentation has been closely associated with vitamin B12, folate and iron deficiencies, as well as methotrexate use, chemotherapy toxicity, uremia, heat stroke, myelodysplasia and Boucher-Neuhäuser Syndrome. Initially, these cytomorphologic changes may easily be overlooked or dismissed as non-specific reactive changes. In this study, we expand our initial observation on our index case to a larger case series. To the best of our knowledge, this is the largest case series to describe the concurrent lymphocyte and unique granulocyte atypia associated with SARS-CoV-2 infection. METHODS Study Design 2,199 patients were hospitalized in the Mount Sinai Health System from Feb 27 to April 2, 2020 with confirmed COVID-19 positivity. Data obtained for this study was covered under an Institutional Review Board (IRB) waiver, HS#:12-00133 GCO#1:12-036(0001-08) Inclusion criteria 50 peripheral blood smears flagged for Pathologist review from March 13 - April 20, 2020 at Mount Sinai Hospital Clinical Hematology Laboratory were included in this study. All suspected COVID-19 cases were confirmed using real-time polymerase chain reaction (RT-PCR) assay to test nasal and pharyngeal swab specimens, per WHO guidelines. Of the 50 COVID-19 positive peripheral blood smears, 39 slides were scanned and imaged with Scopio Labs X100 Full Field Digital Microscope. The X100 provided high resolution oil-immersion level images of large scanned areas. https://scopiolabs.com/hematology/ 19 peripheral blood smears were blindly and independently reviewed by 4 Hematopathologists (CS, PK, JC, JTF), with particular emphasis on granulocyte cytomorphology and percent of hypersegmented neutrophils present (defined as neutrophils with 5 or more nuclear lobes in at least 3% of cells or presence of 6 or more lobes). Atypical lymphocyte morphology was also evaluated and categorized as Downey type I, II, III or plasmacytoid, while monocyte morphology was assessed for unusual nuclear folds and features. Evaluation of platelets and other abnormalities were noted. The presence and degree of significant cytologic atypia was recorded and compared to 20 COVID-19 negative blood smears. RESULTS 16 of the 19 (84%) COVID-19 positive cases showed hypersegmented neutrophils, and all 19 harbored atypical lymphocytes and monocyte morphology, with giant platelets. In contrast, 5 of the 20 (25%) COVID-19 negative cases showed hypersegmented neutrophils, with 2 patients displaying atypical monocytes; none showed atypical lymphocytes or giant platelets (p = 0.022). Concurrent laboratory values showed no evidence of vitamin B12 or folate deficiency. Representative images are summarized in Figure 1 (A-C, 5-6 lobed neutrophils; D-E atypical plasmacytoid lymphocytes, G-I atypical monocytes, J-L giant platelets). CONCLUSION We report atypical hypersegmented neutrophils with toxic cytoplasmic change, atypical monocytes, plasmacytoid lymphocytes, and giant platelets in peripheral blood smears of COVID-19 patients which are significantly higher than in control COVID-19 negative patients. Figure 1 Disclosures Teruya-Feldstein: Edge Anthem: Consultancy.

Hematopathology fellowship education has grown in complexity as patient-centered treatment plans have come to depend on integration of clinical, morphologic, immunophenotypic, molecular, and cytogenetic variables. This complexity is in competition with the need for timely hematopathology care with stewardship of patient, laboratory, and societal resources. Accreditation Council for Graduate Medical Education Milestones provide a guidance document for hematopathology training, but fellows and their educators are in need of a simple framework that allows assessment and feedback of growth toward independent hematopathology practice. Entrustable professional activities provide one such framework, and herein, we provide proposed Hematopathology Fellowship Entrustable Professional Activities based on review of pertinent guidelines and literature, with multiple rounds of expert and stakeholder input utilizing a modified mini-Delphi approach. Ten core entrustable professional activities deemed essential for graduating hematopathology fellows were developed together with skills and knowledge statements, example scenarios, and corresponding Accreditation Council for Graduate Medical Education Milestones. Application of these entrustable professional activities in program design, fellow evaluation, and decisions regarding level of supervision is discussed with consideration of benefits and barriers to implementation. These entrustable professional activities may be used by hematopathology fellowship directors and faculty to provide fellows with timely constructive feedback, determine entrustment decisions, provide the Clinical Competency Committee with granular data to support Milestone evaluations, and provide insight into areas of potential improvement in fellowship training. Fellows will benefit from a clear roadmap to independent hematopathology practice with concrete and timely feedback.

Objectives To assess bone marrow (BM) sampling in academic medical centers. Methods Data from 6,374 BM samples obtained in 32 centers in 2001 and 2011, including core length (CL), were analyzed. Results BM included a biopsy (BMB; 93%) specimen, aspirate (BMA; 92%) specimen, or both (83%). The median (SD) CL was 12 (8.5) mm, and evaluable marrow was 9 (7.6) mm. Tissue contraction due to processing was 15%. BMB specimens were longer in adults younger than 60 years, men, and bilateral, staging, and baseline samples. Only 4% of BMB and 2% of BMB/BMA samples were deemed inadequate for diagnosis. BM for plasma cell dyscrasias, nonphysician operators, and ancillary studies usage increased, while bilateral sampling decreased over the decade. BM-related quality assurance programs are infrequent. Conclusions CL is shorter than recommended and varies with patient age and sex, clinical circumstances, and center experience. While pathologists render diagnoses on most cases irrespective of CL, BMB yield improvement is desirable.

Summary Connecting specific cancer genotypes with phenotypes and drug responses constitutes the central premise of precision oncology but is hindered by the genetic complexity and heterogeneity of primary cancer cells. Here, we use patient-derived induced pluripotent stem cells (iPSCs) and CRISPR/Cas9 genome editing to dissect the individual contributions of two recurrent genetic lesions, the splicing factor SRSF2 P95L mutation and the chromosome 7q deletion, to the development of myeloid malignancy. Using a comprehensive panel of isogenic iPSCs—with none, one, or both genetic lesions—we characterize their relative phenotypic contributions and identify drug sensitivities specific to each one through a candidate drug approach and an unbiased large-scale small-molecule screen. To facilitate drug testing and discovery, we also derive SRSF2-mutant and isogenic normal expandable hematopoietic progenitor cells. We thus describe here an approach to dissect the individual effects of two cooperating mutations to clinically relevant features of malignant diseases., Graphical Abstract, Highlights • A panel of isogenic iPSCs with SRSF2 P95L mutation and del(7q) was generated • The contributions of each genetic lesion to phenotype were separated • Each genetic lesion could be linked to specific therapeutic vulnerabilities • Expandable hematopoietic progenitor cell lines facilitate drug testing, Papapetrou and colleagues develop a comprehensive panel of isogenic iPSC lines with SRSF2 P95L mutation and chr7q deletion. They use these cells to identify cellular phenotypes contributed by each genetic lesion and therapeutic vulnerabilities specific to each one and develop expandable hematopoietic progenitor cell lines to facilitate drug discovery.

Patients with myeloproliferative neoplasms (MPNs) frequently progress to bone marrow failure or acute myeloid leukemia (AML), and mutations in epigenetic regulators such as the metabolic enzyme isocitrate dehydrogenase (IDH) are associated with poor outcomes. Here, we showed that combined expression of Jak2V617Fand mutant IDH1R132Hor Idh2R140Q induces MPN progression, alters stem/progenitor cell function, and impairs differentiation in mice. Jak2V617FIdh2R140Q–mutant MPNs were sensitive to small-molecule inhibition of IDH. Combined inhibition of JAK2 and IDH2 normalized the stem and progenitor cell compartments in the murine model and reduced disease burden to a greater extent than was seen with JAK inhibition alone. In addition, combined JAK2 and IDH2 inhibitor treatment also reversed aberrant gene expression in MPN stem cells and reversed the metabolite perturbations induced by concurrent JAK2 and IDH2 mutations. Combined JAK2 and IDH2 inhibitor therapy also showed cooperative efficacy in cells from MPN patients with both JAK2mutand IDH2mutmutations. Taken together, these data suggest that combined JAK and IDH inhibition May offer a therapeutic advantage in this high-risk MPN subtype., Damon Runyon Cancer Research Foundation (DRG-2241-15), Howard Hughes Medical Institute (Faculty Scholars Award), Stand Up To Cancer, National Cancer Institute (U.S.) (P50CA165962), National Cancer Institute (U.S.) (P30CA14051), Koch Institute for Integrative Cancer Research ( Dana-Farber Harvard Cancer Center Bridge Project), Leukemia & Lymphoma Society of America. Specialized Center of Research (SCOR) Program, National Institutes of Health (U.S.) (grant U54OD020355-01), National Institutes of Health (U.S.) (grant NCI R01CA172636), National Institutes of Health (U.S.) (grant R35CA197594), National Cancer Institute (U.S.) (Cancer Center Support Grant (P30 CA008747).

BACKGROUND Digital pathology and artificial intelligence (AI) are areas of growing interest in pathology. A number of institutes have already integrated digital imaging into routine workflow, relying on AI algorithms for the detection of various cancers and mitotic activity quantification. Despite the use of whole slide imaging (WSI) for tissue evaluation, the field of hematology has lagged behind. While many hospitals rely on limited technologies for automated peripheral blood evaluation (e.g. CellavisionTM), the Scopio LabsTM X100 digital scanner provides high resolution oil-immersion level dynamic images of large scanned areas (https://scopiolabs.com/hematology/). With recent FDA-clearance and newly implemented AI capabilities, the Scopio Labs scanner allows for clear and accurate cytomorphologic characterization and cell quantification for peripheral blood smears (PBS). To this end, we aimed to be one of the few pioneering institutes in the United States to adopt early and implement this technology into our routine workflow as a 'hub and spoke' model for optimized case assessment, data sharing and result reporting across multiple satellite locations within our hospital health system. DESIGN A Scopio x100 digital scanner was deployed at our main hospital site, with an anticipated secondary scanner for installment at a satellite laboratory. PBS flagged for hematopathologist review from two satellite laboratories were scanned, and full-field digitalized slides were evaluated by hematopathologists following AI automated analyses. RESULTS 311 peripheral smears were scanned since April 2021 and representative slides were digitalized at 100x magnification (Figure 1, weblink: https://demo.scopiolabs.com/#/view_scan/9231acaf-f898-4649-950d-a41c26c2baaa) with rapid monolayer, monolayer, full-field, and full-field cytopenia scan options available. The automated AI capabilities classified cells into lineage-specific categories with quantification based on cytomorphologic features (Figure 2). Other AI features include additional cell assignment, cell annotation and comments accessible to all users, finalized report PDF generation, export, upload into our current PowerPath TM software with linkage to the corresponding flow cytometry and bone marrow biopsy reports; and the ability to share digitalized slides with clinicians, laboratory personnel and trainees using uniquely generated weblinks. Images can be used for lectures and tumor boards. Additionally, an 80-case study set for PBS was created for medical students, residents and fellow teaching purposes, including cases displaying acute B-cell lymphoblastic leukemia (B-ALL), acute myelomonocytic leukemia (AMML), hypersegmented neutrophils in COVID-19(+) patients, myelodysplastic syndrome (MDS), atypical lymphocytes, hemoglobinopathies, platelet disorders and various lymphomas. Overall improvements were made to the following areas: CLINICAL WORK/DIAGNOSIS 1. Time-saving due to pre-categorization of cells into lineage-specific groups for pathologist review 2. Minimizes subjectivity in cell counting and cellularity assessment EDUCATION 1. Case-based collection with flow and molecular being maintained here 2. Efficient case retrieval with retained annotations/comments for teaching purposes 3. Wide array of digitalized images for hematology atlas and publications ARCHIVING 1. Collection of reference images (intra/inter departmental) for an array of morphological entities for clinical reference and refined diagnosis (e.g. Bethesda reference images for pap by ASC) 2. Digital catalogue for long-term case follow-up and retrospective review CONCLUSION The Scopio Labs X100 digital system provides an efficient and cost-effective web-based tool to streamline clinical workflow and enhance PBS evaluation. With its recent AI capabilities of cell quantification, lineage-assignment and report-generation, we aim to continue our efforts to fully integrate Scopio Labs into our routine daily clinical workflow for reviewing PBS specimens. CONFLICT OF INTEREST STATEMENT The authors have nothing to disclose with regard to the submitted work Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

Professional medical conferences over the past five years have seen an enormous increase in the use of Twitter in real-time, also known as "live-tweeting". At the United States and Canadian Academy of Pathology (USCAP) 2015 annual meeting, 24 attendees (the authors) volunteered to participate in a live-tweet group, the #InSituPathologists. This group, along with other attendees, kept the world updated via Twitter about the happenings at the annual meeting. There were 6,524 #USCAP2015 tweets made by 662 individual Twitter users; these generated 5,869,323 unique impressions (potential tweet-views) over a 13-day time span encompassing the dates of the annual meeting. Herein we document the successful implementation of the first official USCAP annual meeting live-tweet group, including the pros/cons of live-tweeting and other experiences of the original #InSituPathologists group members. No prior peer-reviewed publications to our knowledge have described in depth the use of an organized group to "live-tweet" a pathology meeting. We believe our group to be the first of its kind in the field of pathology.

We are reporting a case of a 27-year-old woman with a history of swelling in the left submandibular region. This swelling was associated with a mass, and this was pathologically confirmed to be an extranodal marginal zone lymphoma (MALT). The patient underwent surgical excision and postoperative adjuvant radiation therapy. The patient tolerated treatments well and remains free of disease. Here, we describe the case and management described in the current literature.

Mantle Cell Lymphoma (MCL) is characterized by the t(11;14)(q13;q32) translocation. This hallmark oncogenic event transposes CCND1 (11q13) under the control of the immunoglobin heavy chain (IGH) locus (14q32) resulting in constitutive cyclin D1 expression. Although Cyclin D1 (CCND1) overexpression is a key hallmark of MCL, CCND1 overexpressing murine models do not effectively recapitulate the MCL phenotype. Our published data demonstrated that SOX11 binds and regulates components in multiple oncogenic pathways in MCL (Kuo et. al., Oncogene 2015). Furthermore, we recently demonstrated that SOX11 promotes BCR signaling to drive MCL-like pathogenesis utilizing a SOX11 overexpressing (Eu-SOX11) murine model (Kuo et. al., Blood 2018). Given that the majority of classic human MCL co-express CCND1 and SOX11, we hypothesize that these oncogenes may cooperate to drive the pathogenesis of classical MCL. To study in vivo cooperation between CCND1 and SOX11, we crossed Eu-SOX11 mice with Eu-CCND1 mice to generate Eu-SOX11:CCND1 double transgenic (DT) mice. We have previously reported an significant increase in the fraction of CD5+CD19+CD23- MCL cells in the peripheral blood, spleens, lymph nodes and bone marrow of Eu-SOX11 mice and this fraction was further enhanced in DT mice (Fig.1A). We have now conducted a 2-year survival analysis on all 4 genotypes and found significantly reduced survival in DT as compared to Eu-SOX11 mice (Fig.1B). Median survival in DT mice is 16.5 months as compared to 19.7 months in Eu-SOX11 mice. Taken together, our results demonstrate a B-cell specific in vivo cooperation between SOX11 and CCND1 towards promoting a lethal MCL phenotype. RNA sequencing of splenocytes from DT versus SOX11-Tg mice showed significant enrichment of E2F1 target genes (p We have developed small molecule SOX11 inhibitors using a SOX11-DNA homology model we built using the crystal structure of the SOX4-DNA binding domain as a template. SOX11 small molecular inhibitors in combination with CDK4 inhibitors will be used to further dissect the mechanism of cooperation between SOX11 and CCND1 and develop a therapeutic strategy for MCL that is mechanistically distinct from BTK or Bcl-2 inhibition. Disclosures Teruya-Feldstein: Edge Anthem: Consultancy. Parekh:Karyopharm: Research Funding; Celgene: Research Funding; Foundation Medicine: Consultancy.

Summary Genetic and functional studies underscore the central role of JAK/STAT signaling in myeloproliferative neoplasms (MPNs). However, the mechanisms that mediate transformation in MPNs are not fully delineated, and clinically utilized JAK inhibitors have limited ability to reduce disease burden or reverse myelofibrosis. Here we show that MPN progenitor cells are characterized by marked alterations in gene regulation through differential enhancer utilization, and identify nuclear factor κB (NF-κB) signaling as a key pathway activated in malignant and non-malignant cells in MPN. Inhibition of BET bromodomain proteins attenuated NF-κB signaling and reduced cytokine production in vivo . Most importantly, combined JAK/BET inhibition resulted in a marked reduction in the serum levels of inflammatory cytokines, reduced disease burden, and reversed bone marrow fibrosis in vivo .

Supporting tumor suppression The protein PTEN is a phosphatase and tumor suppressor whose activity is often decreased in human cancers. Thus, reactivating such a protein could potentially be an effective therapy against cancer. Lee et al. identified a ubiquitin E3 ligase (WWP1) as a PTEN-interacting protein that modifies PTEN and inhibits its tumor suppressive activity (see the Perspective by Parsons). Depletion of WWP1 increased dimerization and membrane recruitment of PTEN. A natural compound found to be a pharmacological inhibitor of WWP1 inhibited tumor growth in a mouse model of prostate cancer. Thus, reactivation of the tumor suppressor PTEN may provide a strategy for battling tumors. Science , this issue p. eaau0159 ; see also p. 633

There are multiple prognostic indicators for Diffuse large B-cell lymphoma (DLBCL) including; the International Prognostic Index (IPI), and gene expression profiling (GEP) to classify the disease into germinal center B-cell and activated B-cell subtypes, the latter harboring inferior prognosis. More recently, tumor-associated-macrophages (TAM) and lymphocyte-to-monocyte ratio (LMR) were found to have prognostic implications in DLBCL. However, consensus is yet to be reached in terms of the significance of each. In this study, we evaluated the prognostic value of tumor-associated-macrophages (TAM) as assessed by CD163 or CD68 positivity by IHC on tissue biopsies and lymphocyte-to-monocyte ratio (LMR) was calculated from peripheral blood differential, with focus on the inclusion of rituximab as a treatment modality. The number of CD68-positive cells in the tumor microenvironment did not exhibit significant prognostic value, whereas higher number of CD163-positive cells was associated with inferior OS in patients treated with chemotherapy alone. This effect was no longer evident in patients treated with rituximab containing chemo-immunotherapy. On the other hand, the prognostic significance of LMR on survival was more persistent regardless of treatment. There was no association between LMR and the number of CD163-positive cells. Our results suggest that LMR is the more easily and widely available prognostic marker in this era of chemo-immunotherapy. Our finding supports previous literature that the effect of TAM can vary according to treatment. Interaction between rituximab and TAM warrant further scientific investigation for mechanistic insights into targeted therapeutics.

OBJECTIVES: To assess bone marrow (BM) sampling in academic medical centers. METHODS: Data from 6,374 BM samples obtained in 32 centers in 2001 and 2011, including core length (CL), were analyzed. RESULTS: BM included a biopsy (BMB; 93%) specimen, aspirate (BMA; 92%) specimen, or both (83%). The median (SD) CL was 12 (8.5) mm, and evaluable marrow was 9 (7.6) mm. Tissue contraction due to processing was 15%. BMB specimens were longer in adults younger than 60 years, men, and bilateral, staging, and baseline samples. Only 4% of BMB and 2% of BMB/BMA samples were deemed inadequate for diagnosis. BM for plasma cell dyscrasias, nonphysician operators, and ancillary studies usage increased, while bilateral sampling decreased over the decade. BM-related quality assurance programs are infrequent. CONCLUSIONS: CL is shorter than recommended and varies with patient age and sex, clinical circumstances, and center experience. While pathologists render diagnoses on most cases irrespective of CL, BMB yield improvement is desirable.

Vitamin B12 (B12) deficiency in infancy can present with nonspecific symptoms. We report a 5-month old exclusively breastfed full-term infant with emesis, lethargy, progressive pancytopenia, hemolysis, hypofibrinogenemia, elevated lactate dehydrogenase and a hypercellular bone marrow with dyserythropoiesis. The B12 level in the serum was undetectable. The infant's lethargy resolved within 48 hours of intramuscular B12 injection, followed by rapid improvement of pancytopenia. The asymptomatic mother had a normal hemoglobin and mean corpuscular volume, but undetectable B12 level and positive antibodies to intrinsic factor, consistent with pernicious anemia masked by folate supplementation in the mother but causing symptoms in her infant.

Supplemental Digital Content is available in the text, Despite recent advances, the myeloproliferative neoplasms (MPNs) are attended by considerable morbidity and mortality. Janus kinase (Jak) inhibitors such as ruxolitinib manage symptoms but do not substantially change the natural history of the disease. In this report, we show the effects of IMG-7289, an irreversible inhibitor of the epigenetically active lysine-specific demethylase 1 (LSD1) in mouse models of MPN. Once-daily treatment with IMG-7289 normalized or improved blood cell counts, reduced spleen volumes, restored normal splenic architecture, and reduced bone marrow fibrosis. Most importantly, LSD1 inhibition lowered mutant allele burden and improved survival. IMG-7289 selectively inhibited proliferation and induced apoptosis of JAK2 V617F cells by concomitantly increasing expression and methylation of p53, and, independently, the pro-apoptotic factor PUMA and by decreasing the levels of its antiapoptotic antagonist BCLXL. These data provide a molecular understanding of the disease-modifying activity of the LSD1 inhibitor IMG-7289 that is currently undergoing clinical evaluation in patients with high-risk myelofibrosis. Moreover, low doses of IMG-7289 and ruxolitinib synergize in normalizing the MPN phenotype in mice, offering a rationale for investigating combination therapy.

Few studies have examined melanoma and non-melanoma skin cancer (NMSC) incidence rates after a diagnosis of hairy cell leukaemia (HCL). We assessed 267 HCL patients treated at Memorial Sloan Kettering Cancer Center (MSKCC) and Surveillance, Epidemiology and End Results (SEER) data for melanoma and NMSC incidence rates after HCL. Incidence data from MSKCC patients demonstrated a 10-year combined melanoma and NMSC skin cancer rate of 11·3%, melanoma 4·4% and NMSC 6·9%. Molecular analysis of skin cancers from MSKCC patients revealed activating RAS mutations in 3/9 patients, including one patient with melanoma. Of 4750 SEER patients with HCL, 55 (1·2%) had a subsequent diagnosis of melanoma. Standardized incidence ratios (SIRs) did not show that melanoma was more common in HCL patients versus the general population (SIR 1·3, 95% CI 0·78-2·03). Analysis of SEER HCL patients diagnosed before and after 1990 (approximately before and after purine analogue therapy was introduced) showed no evidence of an increased incidence after 1990. A better understanding of any potential association between HCL and skin cancer is highly relevant given ongoing trials using BRAF inhibitors, such as vemurafenib, for relapsed HCL, as RAS-mutant skin cancers could be paradoxically activated in these patients.

The identification of JAK2/MPL mutations in patients with myeloproliferative neoplasms (MPN) has led to the clinical development of JAK kinase inhibitors, including ruxolitinib. Ruxolitinib reduces splenomegaly and systemic symptoms in myelofibrosis and improves overall survival; however, the mechanism by which JAK inhibitors achieve efficacy has not been delineated. Patients with MPN present with increased levels of circulating proinflammatory cytokines, which are mitigated by JAK inhibitor therapy. We sought to elucidate mechanisms by which JAK inhibitors attenuate cytokine-mediated pathophysiology. Single-cell profiling demonstrated that hematopoietic cells from myelofibrosis models and patient samples aberrantly secrete inflammatory cytokines. Pan-hematopoietic Stat3 deletion reduced disease severity and attenuated cytokine secretion, with similar efficacy as observed with ruxolitinib therapy. In contrast, Stat3 deletion restricted to MPN cells did not reduce disease severity or cytokine production. Consistent with these observations, we found that malignant and nonmalignant cells aberrantly secrete cytokines and JAK inhibition reduces cytokine production from both populations. Significance: Our results demonstrate that JAK–STAT3-mediated cytokine production from malignant and nonmalignant cells contributes to MPN pathogenesis and that JAK inhibition in both populations is required for therapeutic efficacy. These findings provide novel insight into the mechanisms by which JAK kinase inhibition achieves therapeutic efficacy in MPNs. Cancer Discov; 5(3); 316–31. ©2015 AACR. See related commentary by Belver and Ferrando, p. 234 This article is highlighted in the In This Issue feature, p. 213

Primary pancreatic lymphoma (PPL) is a rare tumor that is often misdiagnosed. Clinicopathologic features, optimal therapy, and outcomes are not well defined. We reviewed our institutional experience with PPL.Search of our institutional database identified that between 1987-2012, 21,760 patients with lymphoma and 11,286 patients with a primary pancreatic tumor were evaluated. There were 44 patients with pathologically confirmed PPL. Clinical data were obtained by chart review and survival distributions were estimated using the Kaplan-Meier method and compared using the log-rank test.At baseline, LDH was elevated in 55 % of the patients, CA 19-9 in 25 %, and CEA in 20 %. Imaging characteristics included large, unresectable tumors (67 %), and lymphadenopathy inferior to the renal vein (50 %). Twenty-three patients underwent surgery for resection (5), diagnosis (13), or palliation (5). Chemotherapy alone achieved a 75 % complete response rate. Eight patients experienced relapse, 88 % of which occurred at distant sites. Median overall survival was 6.1 years and 10-year disease-specific survival (DSS) was 69 %. Patients with a low risk International Prognostic Index (IPI) and those with a follicular histologic subtype demonstrated 5-year DSS of 100 %.Chemotherapy for PPL results in a high complete response rate and long DSS, which is similar to nodal non-Hodgkin's lymphoma (NHL). A favorable outcome is expected for IPI low risk patients and follicular histologic subtype. Systemic therapy should generally be the initial therapy when the diagnosis is known. Prolonged follow up is recommended to detect relapses. Surgery alone should be reserved for non-curative intent (i.e. diagnostic or palliative).

The translational control of oncoprotein expression is implicated in many cancers. Here we report an eIF4A RNA helicase-dependent mechanism of translational control that contributes to oncogenesis and underlies the anticancer effects of silvestrol and related compounds. For example, eIF4A promotes T-cell acute lymphoblastic leukaemia development in vivo and is required for leukaemia maintenance. Accordingly, inhibition of eIF4A with silvestrol has powerful therapeutic effects against murine and human leukaemic cells in vitro and in vivo. We use transcriptome-scale ribosome footprinting to identify the hallmarks of eIF4A-dependent transcripts. These include 5′ untranslated region (UTR) sequences such as the 12-nucleotide guanine quartet (CGG)4 motif that can form RNA G-quadruplex structures. Notably, among the most eIF4A-dependent and silvestrol-sensitive transcripts are a number of oncogenes, superenhancer-associated transcription factors, and epigenetic regulators. Hence, the 5′ UTRs of select cancer genes harbour a targetable requirement for the eIF4A RNA helicase. The translation of many messenger RNAs that encode important oncogenes and transcription factors depends on the eIF4A RNA helicase to resolve G-quadruplex structures, implying eIF4A inhibition as an effective cancer therapy. The expression of some oncoproteins is regulated at the translational level. Hans-Guido Wendel and colleagues show that a subset of oncoprotein- and transcription factor-encoding mRNAs that are dependent on the translation initiation factor eIF4A contain a G-quadruplex-forming structure in their 5′ untranslated regions. These findings explain why silvestrol, a plant-derived anticancer agent that targets eIF4A-dependent translation, is not generally toxic but can be well tolerated except in cancer cells which are dependent on the activities of these proteins. In a separate study in this issue, Stephan Vagner and colleagues show that inhibition of eIF4F cooperates with BRAF inhibitors in reducing the growth of melanomas linked to BRAF mutations.

PTEN encodes a lipid phosphatase that is underexpressed in many cancers owing to deletions, mutations or gene silencing. PTEN dephosphorylates phosphatidylinositol (3,4,5)-triphosphate, thereby opposing the activity of class I phosphatidylinositol 3-kinases that mediate growth- and survival-factor signalling through phosphatidylinositol 3-kinase effectors such as AKT and mTOR. To determine whether continued PTEN inactivation is required to maintain malignancy, here we generate an RNA interference-based transgenic mouse model that allows tetracycline-dependent regulation of PTEN in a time- and tissue-specific manner. Postnatal Pten knockdown in the haematopoietic compartment produced highly disseminated T-cell acute lymphoblastic leukaemia. Notably, reactivation of PTEN mainly reduced T-cell leukaemia dissemination but had little effect on tumour load in haematopoietic organs. Leukaemia infiltration into the intestine was dependent on CCR9 G-protein-coupled receptor signalling, which was amplified by PTEN loss. Our results suggest that in the absence of PTEN, G-protein-coupled receptors may have an unanticipated role in driving tumour growth and invasion in an unsupportive environment. They further reveal that the role of PTEN loss in tumour maintenance is not invariant and can be influenced by the tissue microenvironment, thereby producing a form of intratumoral heterogeneity that is independent of cancer genotype.

Cells of the osteoblast lineage affect the homing and the number of long-term repopulating haematopoietic stem cells, haematopoietic stem cell mobilization and lineage determination and B cell lymphopoiesis. Osteoblasts were recently implicated in pre-leukaemic conditions in mice. However, a single genetic change in osteoblasts that can induce leukaemogenesis has not been shown. Here we show that an activating mutation of β-catenin in mouse osteoblasts alters the differentiation potential of myeloid and lymphoid progenitors leading to development of acute myeloid leukaemia with common chromosomal aberrations and cell autonomous progression. Activated β-catenin stimulates expression of the Notch ligand jagged 1 in osteoblasts. Subsequent activation of Notch signalling in haematopoietic stem cell progenitors induces the malignant changes. Genetic or pharmacological inhibition of Notch signalling ameliorates acute myeloid leukaemia and demonstrates the pathogenic role of the Notch pathway. In 38% of patients with myelodysplastic syndromes or acute myeloid leukaemia, increased β-catenin signalling and nuclear accumulation was identified in osteoblasts and these patients showed increased Notch signalling in haematopoietic cells. These findings demonstrate that genetic alterations in osteoblasts can induce acute myeloid leukaemia, identify molecular signals leading to this transformation and suggest a potential novel pharmacotherapeutic approach to acute myeloid leukaemia.

SUMMARY The Ten-eleven translocation (TET) enzymes regulate gene expression by promoting DNA demethylation and partnering with chromatin modifiers. TET2, a member of this family, is frequently mutated in hematological disorders. The contributions of TET2 in hematopoiesis have been attributed to its DNA demethylase activity, and the significance of its nonenzymatic functions has remained undefined. To dissect the catalytic and non-catalytic requirements of Tet2, we engineered catalytically inactive Tet2 mutant mice and conducted comparative analyses of Tet2 mutant and Tet2 knockout animals. Tet2 knockout mice exhibited expansion of hematopoietic stem and progenitor cells (HSPCs) and developed myeloid and lymphoid disorders, while Tet2 mutant mice predominantly developed myeloid malignancies reminiscent of human myelodysplastic syndromes. HSPCs from Tet2 knockout mice exhibited distinct gene expression profiles, including downregulation of Gata2. Overexpression of Gata2 in Tet2 knockout bone marrow cells ameliorated disease phenotypes. Our results reveal the non-catalytic roles of TET2 in HSPC homeostasis., In Brief The DNA demethylase TET2 is commonly mutated in hematological disorders, but the significance of its enzymatic versus nonenzymatic roles in hematopoiesis remains undefined. Using Tet2 catalytic-mutant and knockout mice, Ito et al. find that Tet2 enzymatic activity is critical for myelopoiesis, while aberrant lymphopoiesis is mainly associated with complete loss of Tet2., Graphical Abstract

[Figure][1] An 80-year-old man with a 20-year history of T-cell large granular lymphocytic leukemia (T-LGL), receiving low-dose neupogen for neutropenia, presented with new-onset fever, pancytopenia, and tachycardia. Flow cytometry of the peripheral blood showed aberrant clonal T cells (6%

Background Growing evidence demonstrates that an increased number of CD68 positive tumor-associated macrophages (TAM) is associated with decreased survival in patients with newly diagnosed classic Hodgkin lymphoma (HL). However, the impact of TAM in relapsed and refractory disease is unknown. Design and methods To investigate whether the presence of elevated CD68 retains its prognostic significance in the relapsed and refractory setting, we analyzed pre-salvage biopsy specimens of 81 patients with relapsed and refractory HL using a tissue microarray. Scoring of CD68 was based on the percentage of CD68 positive TAM compared to the total number of cells in representative areas. The final percent of CD68 positivity for each case was based on the average of cores available for examination. Results In a univariate analysis, we found that patients with elevated levels of CD68 positive TAM had inferior overall survival (OS) compared with patients who had lower CD68 levels. For patients undergoing autologous stem cell transplant after salvage treatment, elevated CD68 levels were predictive of both adverse OS and event free survival. However, after adjusting for other variables, increased CD68 positive TAM did not retain prognostic significance in a multivariate model. Conclusions In our dataset of primary refractory and relapsed Hodgkin lymphoma biopsy specimens, TAM infiltration is unable to definitively predict outcome. In order to validate these findings, TAM infiltration of relapsed and refractory specimens should be assessed prospectively and paired to initial Hodgkin lymphoma biopsies at diagnosis.

We present here the first report of an adult patient with simultaneous LCH and AML with t(9;11).5

SummaryMicroRNAs are frequently deregulated in cancer. Here we show that miR-22 is upregulated in myelodysplastic syndrome (MDS) and leukemia and its aberrant expression correlates with poor survival. To explore its role in hematopoietic stem cell function and malignancy, we generated transgenic mice conditionally expressing miR-22 in the hematopoietic compartment. These mice displayed reduced levels of global 5-hydroxymethylcytosine (5-hmC) and increased hematopoietic stem cell self-renewal accompanied by defective differentiation. Conversely, miR-22 inhibition blocked proliferation in both mouse and human leukemic cells. Over time, miR-22 transgenic mice developed MDS and hematological malignancies. We also identify TET2 as a key target of miR-22 in this context. Ectopic expression of TET2 suppressed the miR-22-induced phenotypes. Downregulation of TET2 protein also correlated with poor clinical outcomes and miR-22 overexpression in MDS patients. Our results therefore identify miR-22 as a potent proto-oncogene and suggest that aberrations in the miR-22/TET2 regulatory network are common in hematopoietic malignancies.

Lipids, either endogenously synthesized or exogenous, have been linked to human cancer. Here we found that PML is frequently co-deleted with PTEN in metastatic human prostate cancer (CaP). We demonstrated that conditional inactivation of Pml in the mouse prostate morphs indolent Pten-null tumors into lethal metastatic disease. We identified MAPK reactivation, subsequent hyperactivation of an aberrant SREBP prometastatic lipogenic program, and a distinctive lipidomic profile as key characteristic features of metastatic Pml and Pten double-null CaP. Furthermore, targeting SREBP in vivo by fatostatin blocked both tumor growth and distant metastasis. Importantly, a high-fat diet (HFD) induced lipid accumulation in prostate tumors and was sufficient to drive metastasis in a nonmetastatic Pten-null mouse model of CaP, and an SREBP signature was highly enriched in metastatic human CaP. Thus, our findings uncover a prometastatic lipogenic program and lend direct genetic and experimental support to the notion that a Western HFD can promote metastasis.

International audience; The HVEM (TNFRSF14) receptor gene is among the most frequently mutated genes in germinal center lymphomas. We report that loss of HVEM leads to cell-autonomous activation of B cell proliferation and drives the development of GC lymphomas in vivo. HVEM-deficient lymphoma B cells also induce a tumor-supportive microenvironment marked by exacerbated lymphoid stroma activation and increased recruitment of T follicular helper (T-FH) cells. These changes result from the disruption of inhibitory cell-cell interactions between the HVEM and BTLA (B and T lymphocyte attenuator) receptors. Accordingly, administration of the HVEM ectodomain protein (solHVEM ((P37-V202))) binds BTLA and restores tumor suppression. To deliver solHVEM to lymphomas in vivo, we engineered CD19-targeted chimeric antigen receptor (CAR) T cells that produce solHVEM locally and continuously. These modified CAR-T cells show enhanced therapeutic activity against xenografted lymphomas. Hence, the HVEM-BTLA axis opposes lymphoma development, and our study illustrates the use of CAR-T cells as "micro-pharmacies'' able to deliver an anti-cancer protein.

JAK1 is a critical effector of pro-inflammatory cytokine signaling and plays important roles in immune function, while abnormal JAK1 activity has been linked to immunological and neoplastic diseases. Specific functions of JAK1 in the context of hematopoiesis, and specifically within hematopoietic stem cells (HSCs), have not clearly been delineated. Here, we show that conditional Jak1 loss in HSCs reduces their self-renewal and markedly alters lymphoid/myeloid differentiation invivo. Jak1-deficient HSCs exhibit decreased competitiveness invivo and are unable to rescue hematopoiesis in the setting of myelosuppression. They exhibit increased quiescence, an inability to enter the cell cycle in response to hematopoietic stress, and a marked reduction in cytokine sensing, including in response to type I interferons and IL-3. Moreover, Jak1 loss is not fully rescued byexpression of a constitutively active Jak2 allele. Together, these data highlight an essential role for Jak1 in HSC homeostasis and stress responses.

A single hematopoietic stem cell (HSC) is capable of reconstituting hematopoiesis and maintaining homeostasis by balancing self-renewal and cell differentiation. The mechanisms of HSC division balance, however, are not yet defined. Here we demonstrate, by characterizing at the single-cell level a purified and minimally heterogeneous murine Tie2+ HSC population, that these top hierarchical HSCs preferentially undergo symmetric divisions. The induction of mitophagy, a quality control process in mitochondria, plays an essential role in self-renewing expansion of Tie2+ HSCs. Activation of the PPAR (peroxisome proliferator–activated receptor)–fatty acid oxidation pathway promotes expansion of Tie2+ HSCs through enhanced Parkin recruitment in mitochondria. These metabolic pathways are conserved in human TIE2+ HSCs. Our data thus identify mitophagy as a key mechanism of HSC expansion and suggest potential methods of cell-fate manipulation through metabolic pathways.

To ascertain the genetic basis of pediatric Burkitt lymphoma (pBL), we performed clinical-grade next-generation sequencing of 182 cancer-related genes on 29 formalin-fixed, paraffin embedded primary pBL samples. Ninety percent of cases had at least one mutation or genetic alteration, most commonly involving MYC and TP53. EBV(−) cases were more likely than EBV(+) cases to have multiple mutations (P < .0001). Alterations in tumor-related genes not previously described in BL were identified. Truncating mutations in ARID1A, a member of the SWI/SNF nucleosome remodeling complex, were seen in 17% of cases. MCL1 pathway alterations were found in 22% of cases and confirmed in an expanded panel. Other clinically relevant genomic alterations were found in 20% of cases. Our data suggest the roles of MCL1 and ARID1A in BL pathogenesis and demonstrate that comprehensive genomic profiling may identify additional treatment options in refractory disease.

Dyskeratosis congenita (DC) is a rare inherited disorder characterized by bone marrow failure and cancer predisposition. We present a case of a 28-year-old woman with DC who was admitted for hematopoietic stem cell transplantation (HSCT) for aplastic anemia and who developed acute myeloid leukemia with complex genetic karyotype abnormalities including the MLL (11q23) gene, 1q25, and chromosome 8. After transplantation, a monomorphic Epstein–Barr virus (EBV) negative posttransplant-associated lymphoproliferative disorder (PTLD) diffuse large B-cell lymphoma was discovered involving the liver, omental tissue, and peritoneal fluid samples showing additional MLL (11q23) gene abnormalities by fluorescence in situ hybridization. Despite treatment, the patient died of complications associated with transplantation and invasive fungal infection. This case represents the first bona fide documented case of EBV-negative monomorphic PTLD host derived, with MLL gene abnormalities in a patient with DC, and shows another possible mechanism for the development of a therapy-related lymphoid neoplasm after transplantation.

Summary Aberrant Skp2 signaling has been implicated as a driving event in tumorigenesis. Although the underlying molecular mechanisms remain elusive, cytoplasmic Skp2 correlates with more aggressive forms of breast and prostate cancers. Here, we report that Skp2 is acetylated by p300 at K68 and K71, which is a process that can be antagonized by the SIRT3 deacetylase. Inactivation of SIRT3 leads to elevated Skp2 acetylation, which leads to increased Skp2 stability through impairment of the Cdh1-mediated proteolysis pathway. As a result, Skp2 oncogenic function is increased, whereby cells expressing an acetylation-mimetic mutant display enhanced cellular proliferation and tumorigenesis in vivo. Moreover, acetylation of Skp2 in the nuclear localization signal (NLS) promotes its cytoplasmic retention, and cytoplasmic Skp2 enhances cellular migration through ubiquitination and destruction of E-cadherin. Thus, our study identifies an acetylation-dependent regulatory mechanism governing Skp2 oncogenic function and provides insight into how cytoplasmic Skp2 controls cellular migration.

Tumour suppressor genes encode a broad class of molecules whose mutational attenuation contributes to malignant progression. In the canonical situation, the tumour suppressor is completely inactivated through a two-hit process involving a point mutation in one allele and chromosomal deletion of the other1. Here, to identify tumour suppressor genes in lymphoma, we screen a short hairpin RNA library targeting genes deleted in human lymphomas. We functionally identify those genes whose suppression promotes tumorigenesis in a mouse lymphoma model. Of the nine tumour suppressors we identified, eight correspond to genes occurring in three physically linked ‘clusters’, suggesting that the common occurrence of large chromosomal deletions in human tumours reflects selective pressure to attenuate multiple genes. Among the new tumour suppressors are adenosylmethionine decarboxylase 1 (AMD1) and eukaryotic translation initiation factor 5A (eIF5A), two genes associated with hypusine, a unique amino acid produced as a product of polyamine metabolism through a highly conserved pathway2. Through a secondary screen surveying the impact of all polyamine enzymes on tumorigenesis, we establish the polyamine–hypusine axis as a new tumour suppressor network regulating apoptosis. Unexpectedly, heterozygous deletions encompassing AMD1 and eIF5A often occur together in human lymphomas and co-suppression of both genes promotes lymphomagenesis in mice. Thus, some tumour suppressor functions can be disabled through a two-step process targeting different genes acting in the same pathway.

Loss of major histocompatibility complex class II (MHC II) expression is associated with poor patient outcome in diffuse large B-cell lymphoma (DLBCL). As MHC II molecules are lost with plasmacytic differentiation in normal cells, we asked whether MHC II loss in DLBCL is associated with an altered differentiation state. We used gene expression profiling, quantum dots, and immunohistochemistry to study the relationship between MHC II and plasma cell markers in DLBCL and plasmablastic lymphoma (PBL). Results demonstrate that MHC II(−) DLBCL immunophenotypically overlap with PBL and demonstrate an inverse correlation between MHC II and plasma cell markers MUM1, PRDM1/Blimp1, and XBP1s. In addition, MHC II expression is significantly higher in germinal center-DLBCL than activated B cell-DLBCL. A minor subset of cases with an unusual pattern of mislocalized punctate MHC II staining and intermediate levels of mRNA is also described. Finally, we show that PBL is negative for MHC II. The results imply a spectrum of MHC II expression that is more frequently diminished in tumors derived from B cells at the later stages of differentiation (with complete loss in PBL). Our observations provide a possible unifying concept that may contribute to the poor outcome reported in all MHC II(−) B-cell tumors.

Peripheral T-cell non-Hodgkin lymphomas (T-NHL) are rare diseases, with a worse prognosis compared to their B-cell counterparts. Allogeneic hematopoietic stem cell transplant may have a role in the treatment of relapsed/refractory disease or high-risk histologies in the upfront setting. However, there is limited information on the efficacy of allogeneic transplant for these diseases, as well as what factors may predict outcomes. We therefore performed a retrospective study of 34 patients who received an allogeneic transplant for the treatment of T-NHL at a single center between 1 January 1992 and 31 December 2009. The median follow-up for survivors was 45 months (range 9-160 months). The 2-year overall survival (OS) was 0.61 (95% confidence interval [CI]: 0.43-0.75) with a plateau at 28 months. Ki-67 expression ≤ 25% was predictive of improved OS (p0.01), and transplant in complete remission was predictive of a decreased cumulative incidence of events (p = 0.04). Three patients received a donor leukocyte infusion, and two patients demonstrated a response, supporting a graft-versus-lymphoma effect. These data demonstrate that allogeneic transplant is a viable option for the treatment of T-NHL and merits prospective evaluation.

Background: The World Health Organization (WHO) classification of hematologic malignancies, published in 2000, was designed to improve diagnostic accuracy by incorporating the latest in scientific understanding. The impact of the WHO classification on the frequency of diagnostic discrepancy in lymphoma is unknown. Methods: We reviewed all second-opinion pathology of lymphoma at our National Cancer Institute-designated Comprehensive Cancer Center (NCI-CCC) from January to June 2001 and from January to June 2006. Discrepancies between submitted and second-opinion diagnoses were scored based upon an a priori grading schema. Results: Major diagnostic revision was rendered in 65 of 365 cases (17.8%) in 2001 and 58 of 354 (16.4%) in 2006 (P = NS). Including cases reviewed and revised beforehand at another NCI-CCC, rates of major diagnostic revision were 21.4% and 18.6%, respectively (P = NS). Discrepancy rates varied by diagnosis, from Hodgkin lymphoma (10%) to Burkitt's lymphoma (75%). No association was seen for age, gender, race/ethnicity, biopsy type, or nature of referring center. Conclusions: Clinically meaningful diagnostic revision occurs frequently with expert pathology review for a diagnosis of lymphoma. Despite the WHO classification, rates of diagnostic revision at our institution in 2001 and 2006 did not differ significantly. Given the potential harm from misdiagnosis, expert hematopathology review should be considered the standard of care.