Search

Microbial impact on tumorigenesis of heritable cancers proximal to the gut is well-documented. Whether the microbiota influences cancers arising from inborn mutations at sites distal to the gut is undetermined. Using two models of heritable cancer, Trp53 -deficient mice and Wnt1-transgenic mice, and a gnotobiotic approach, we found the microbiota to be inconsequential for tumor development. This work furthers our understanding of the degree of the microbial impact on tumor development., Importance: The influence of the microbiome on the development of cancer is well-documented with many if not all published studies reporting either a positive or a negative impact. None of the published studies, however, presented data on the influence of the microbiome on the development of heritable cancer. We find that the microbiota has no influence on cancer development in two models of spontaneous cancers driven by germline Trp53 deficiency and constitutive Wnt1 signaling.

As a consequence of rapidly developing genetic technologies and advances in the understanding of the pathogenesis of acute myeloid leukemia (AML), the classification of AML has moved gradually from a morphologic and cytochemical-based system to one that is genetically defined. Recent molecular and genetic developments have been integrated into the diagnostic criteria for AML in the fifth edition of the World Health Organization (WHO) Classification of Haematolymphoid Tumours and the 2022 International Consensus Classification (ICC) of Myeloid Neoplasms and Acute Leukemias, expanding the list of genetically defined entities. In this review article, we use a case-based format describing the diagnostic workup, risk stratification, and possible treatment options to highlight the impact of the 2022 WHO and ICC classifications on clinical practice. We show that despite much commentary and anguish, there is a significant overlap between the two classifications. We further highlight the fact that even for entities with divergent nomenclature, such as TP53 -mutated AML, the actual genetic lesion leads to convergent therapy., Competing Interests: Uwe Platzbecker has acted as a consultant or advisor to AbbVie, Takeda, Celgene/BMS, Curis, Jazz Pharmaceuticals, Novartis, and Servier; has received clinical research support to his institution from Astellas, Celgene, Cellectis, Daiichi‐Sankyo, FortySeven/Gilead, Novartis, and Rafael Pharmaceuticals; and has received royalties from UpToDate. Richard A. Larson has acted as a consultant or advisor to AbbVie, Amgen, Ariad/Takeda, Astellas, Celgene/BMS, Curis, CVS/Caremark, Epizyme, Immunogen, Jazz Pharmaceuticals, Kling Biotherapeutics, MedPace, MorphoSys, Novartis, and Servier; has received clinical research support to his institution from Astellas, Celgene, Cellectis, Daiichi‐Sankyo, FortySeven/Gilead, Novartis, and Rafael Pharmaceuticals; and has received royalties from UpToDate. Sandeep Gurbuxani has served as a consultant to AbbVie; has received honoraria from Jazz Pharmaceuticals; and collects royalties from UpToDate., (© 2025 The Author(s). HemaSphere published by John Wiley & Sons Ltd on behalf of European Hematology Association.)

Background: CD58 loss has been described as a mechanism of resistance to blinatumomab and chimeric antigen receptor T-cell therapy, functioning as a modulator of response to T-cell activation., Methods: Using flow cytometry, we evaluated the impact of CD58 mean fluorescence intensity (MFI) on the probability of achieving measurable residual disease (MRD) negativity in patients with B-cell acute lymphoblastic leukemia treated with inotuzumab ozogamicin (InO)., Results: The odds ratio of achieving MRD negativity was 1.03 for every 1000 unit increase in CD58 MFI., Conclusion: Our results suggest that MRD negativity rates after InO are high, regardless of the intensity of CD58 expression., Competing Interests: Adam S. DuVall: speaker for CE Concepts. Wendy Stock: advisor for Kura, Servier, Newave, and Asofarma. Sandeep Gurbuxani: consulting or advisory role: AbbVie, Jazz Pharmaceuticals. Patents, Royalties, Other Intellectual Property: Royalties from UpToDate for contributions to various topics. Anand A. Patel: honoraria from AbbVie, Bristol Myers Squibb, and Sobi; research funding (institutional) from Pfizer, Kronos Bio, and Sumitomo. The rest of the authors declare no conflict of interest., (© 2024 The Author(s). eJHaem published by British Society for Haematology and John Wiley & Sons Ltd.)

Acute myeloid leukemia is characterized by uncontrolled proliferation of self-renewing myeloid progenitors accompanied by a differentiation arrest. PHF6 is a chromatin-binding protein mutated in myeloid leukemias, and its isolated loss increases mouse HSC self-renewal without malignant transformation. We report here that Phf6 knockout increases the aggressiveness of Hoxa9-driven AML over serial transplantation, and increases the frequency of leukemia initiating cells. We define the in vivo hierarchy of Hoxa9-driven AML and identify a population that we term the "LIC-e" (leukemia initiating cells enriched) population. We find that Phf6 loss expands the LIC-e population and skews its transcriptome to a more stem-like state; concordant transcriptome shifts are also observed on PHF6 knockout in a human AML cell line and in PHF6 mutant patient samples from the BEAT AML dataset. We demonstrate that LIC-e accumulation in Phf6 knockout AML occurs not due to effects on cell cycle or apoptosis, but due to an increase in the fraction of its progeny that retain LIC-e identity. Our work indicates that Phf6 loss increases AML self-renewal through context-specific effects on leukemia stem cells., (© 2024. The Author(s).)

Current therapies for high-grade TP53-mutated myeloid neoplasms (≥10% blasts) do not offer a meaningful survival benefit except allogeneic stem cell transplantation in the minority who achieve a complete response to first line therapy (CR1). To identify reliable pre-therapy predictors of complete response to first-line therapy (CR1) and outcomes, we assembled a cohort of 242 individuals with TP53-mutated myeloid neoplasms and ≥10% blasts with well-annotated clinical, molecular and pathology data. Key outcomes examined were CR1 & 24-month survival (OS24). In this elderly cohort (median age 68.2 years) with 74.0% receiving frontline non-intensive regimens (hypomethylating agents +/- venetoclax), the overall cohort CR1 rate was 25.6% (50/195). We additionally identified several pre-therapy factors predictive of inferior CR1 including male gender (P = 0.026), ≥2 autosomal monosomies (P < 0.001), -17/17p (P = 0.011), multi-hit TP53 allelic state (P < 0.001) and CUX1 co-alterations (P = 0.010). In univariable analysis of the entire cohort, inferior OS24 was predicated by ≥2 monosomies (P = 0.004), TP53 VAF > 25% (P = 0.002), TP53 splice junction mutations (P = 0.007) and antecedent treated myeloid neoplasm (P = 0.001). In addition, mutations/deletions in CUX1, U2AF1, EZH2, TET2, CBL, or KRAS ('EPI6' signature) predicted inferior OS24 (HR = 2.0 [1.5-2.8]; P < 0.0001). In a subgroup analysis of HMA +/-Ven treated individuals (N = 144), TP53 VAF and monosomies did not impact OS24. A risk score for HMA +/-Ven treated individuals incorporating three pre-therapy predictors including TP53 splice junction mutations, EPI6 and antecedent treated myeloid neoplasm stratified 3 prognostic distinct groups: intermediate, intermediate-poor, and poor with significantly different median (12.8, 6.0, 4.3 months) and 24-month (20.9%, 5.7%, 0.5%) survival (P < 0.0001). For the first time, in a seemingly monolithic high-risk cohort, our data identifies several baseline factors that predict response and 24-month survival., (© 2024. The Author(s).)

Abstract: The spectrum of myeloid disorders ranges from aplastic bone marrow failure characterized by an empty bone marrow completely lacking in hematopoiesis to acute myeloid leukemia in which the marrow space is replaced by undifferentiated leukemic blasts. Recent advances in the capacity to sequence bulk tumor population as well as at a single-cell level has provided significant insight into the stepwise process of transformation to acute myeloid leukemia. Using models of progression in the context of germ line predisposition (trisomy 21, GATA2 deficiency, and SAMD9/9L syndrome), premalignant states (clonal hematopoiesis and clonal cytopenia of unknown significance), and myelodysplastic syndrome, we review the mechanisms of progression focusing on the hierarchy of clonal mutation and potential roles of transcription factor alterations, splicing factor mutations, and the bone marrow environment in progression to acute myeloid leukemia. Despite major advances in our understanding, preventing the progression of these disorders or treating them at the acute leukemia phase remains a major area of unmet medical need., (© 2024 American Society of Hematology. Published by Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.)

Myeloid neoplasms arise from preexisting clonal hematopoiesis (CH); however, the role of CH in the pathogenesis of acute lymphoblastic leukemia (ALL) is unknown. We found that 18% of adult ALL cases harbored TP53, and 16% had myeloid CH-associated gene mutations. ALL with myeloid mutations (MyM) had distinct genetic and clinical characteristics, associated with inferior survival. By using single-cell proteogenomic analysis, we demonstrated that myeloid mutations were present years before the diagnosis of ALL, and a subset of these clones expanded over time to manifest as dominant clones in ALL. Single-cell RNA sequencing revealed upregulation of genes associated with cell survival and resistance to apoptosis in B-ALL with MyM, which responds better to newer immunotherapeutic approaches. These findings define ALL with MyM as a high-risk disease that can arise from antecedent CH and offer new mechanistic insights to develop better therapeutic and preventative strategies., Significance: CH is a precursor lesion for lymphoblastic leukemogenesis. ALL with MyM has distinct genetic and clinical characteristics, associated with adverse survival outcomes after chemotherapy. CH can precede ALL years before diagnosis, and ALL with MyM is enriched with activated T cells that respond to immunotherapies such as blinatumomab. See related commentary by Iacobucci, p. 142., (©2023 The Authors; Published by the American Association for Cancer Research.)

Data regarding the use of FMS-like tyrosine kinase 3 (FLT3) and isocitrate dehydrogenase 1/2 (IDH1/2) inhibitors in acute lymphoblastic leukaemia (ALL) are lacking. We identified 14 patients with FLT3- or IDH1/2-mutated ALL. Three early T-cell precursor-ALL patients received FLT3 or IDH2 inhibitors. Patient 1 maintains a complete remission (CR) with enasidenib after intolerance to chemotherapy. Patient 2 maintained a CR for 27 months after treatment with enasidenib for relapsed disease. Patient 3 was treated with venetoclax and gilteritinib at the time of relapse and maintained a CR with gilteritinib for 8 months. These cases suggest that FLT3 and IDH inhibitors could represent a viable therapeutic option for ALL patients with these mutations., (© 2023 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Abstract: Various socioeconomic and biologic factors affect cancer health disparities and differences in health outcomes. To better characterize the socioeconomic vs biologic determinants of acute lymphoblastic leukemia (ALL) outcomes, we conducted a single-institution, retrospective analysis of adult patients with ALL treated at the University of Chicago (UChicago) from 2010 to 2022 and compared our outcomes with the US national data (the Surveillance, Epidemiology, and End Results [SEER] database). Among 221 adult patients with ALL treated at UChicago, BCR::ABL1 was more frequent in patients with higher body mass index (BMI; odds ratio [OR], 7.64; 95% confidence interval [CI], 1.17-49.9) and non-Hispanic Black (NHB) ancestry (59% vs 24% in non-Hispanic White (NHW) and 20% in Hispanic patients; P = .001). In a multivariable analysis, age (hazard ratio [HR], 6.93; 95% CI, 2.27-21.1) and higher BMI at diagnosis (HR, 10.3; 95% CI, 2.56-41.5) were independent predictors of poor overall survival (OS). In contrast, race or income were not predictors of OS in the UChicago cohort. Analysis of the national SEER database (2010-2020) demonstrated worse survival outcomes in Hispanic and NHB patients than in NHW patients among adolescent and young adults (AYAs) but not in older adults (aged >40 years). Both AYA and older adult patients with higher median household income had better OS than those with lower income. Therefore, multidisciplinary medical care coupled with essential supportive care services offered at centers experienced in ALL care may alleviate the socioeconomic disparities in ALL outcomes in the United States., (© 2024 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Microbial impact on tumorigenesis of heritable cancers proximal to the gut is well documented. Whether the microbiota influences cancers arising from inborn mutations at sites distal to the gut is undetermined. Using two models of heritable cancer, we found the microbiota to be inconsequential for tumor development. However, the type of tumor that develops may be influenced by the microbiota. This work furthers our understanding of the microbial impact on tumor development.

GATA1 mutations that result in loss of the N-terminal 83 amino acids are a feature of myeloid leukemia in children with Down syndrome, rare familial cases of dyserythropoietic anemia, and a subset of cases of Diamond-Blackfan anemia. The Gata1s mouse model, which expresses only the short GATA1 isoform that begins at methionine 84, has been shown to have a defect in hematopoiesis, especially impaired erythropoiesis with expanded megakaryopoiesis, during gestation. However, these mice reportedly did not show any postnatal phenotype. Here, we demonstrate that Gata1s mutant mice display macrocytic anemia and features of aberrant megakaryopoiesis throughout life, culminating in profound splenomegaly and bone marrow fibrosis. These data support the use of this animal model for studies of GATA1 deficiencies., (© 2023 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Myeloid malignancies are a manifestation of clonal expansion of hematopoietic cells driven by somatic genetic alterations that may arise in a potential background of deleterious germline variants. As next-generation sequencing technology has become more accessible, real-world experience has allowed integration of molecular genomic data with morphology, immunophenotype, and conventional cytogenetics to refine our understanding of myeloid malignancies. This has prompted revisions in the classification and the prognostication schema of myeloid malignancies and germline predisposition to hematologic malignancies. This review provides an overview of significant changes in the recently published classifications of AML and myelodysplastic syndrome, emerging prognostic scoring, and the role of germline deleterious variants in predisposing to MDS and AML.

-7/del(7q) is prevalent across subtypes of myeloid neoplasms. CUX1, located on 7q22, encodes a homeodomain-containing transcription factor, and, like -7/del(7q), CUX1 inactivating mutations independently carry a poor prognosis. As with loss of 7q, CUX1 mutations often occur early in disease pathogenesis. We reported that CUX1 deficiency causes myelodysplastic syndrome in mice but was insufficient to drive acute myeloid leukemia (AML). Given the known association between -7/del(7q) and RAS pathway mutations, we mined cancer genome databases and explicitly linked CUX1 mutations with oncogenic RAS mutations. To determine if activated RAS and CUX1 deficiency promote leukemogenesis, we generated mice bearing Nras G12D and CUX1-knockdown which developed AML, not seen in mice with either mutation alone. Oncogenic RAS imparts increased self-renewal on CUX1-deficient hematopoietic stem/progenitor cells (HSPCs). Reciprocally, CUX1 knockdown amplifies RAS signaling through reduction of negative regulators of RAS/PI3K signaling. Double mutant HSPCs were responsive to PIK3 or MEK inhibition. Similarly, low expression of CUX1 in primary AML samples correlates with sensitivity to the same inhibitors, suggesting a potential therapy for malignancies with CUX1 inactivation. This work demonstrates an unexpected convergence of an oncogene and tumor suppressor gene on the same pathway., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Myelofibrosis (MF) is a disease associated with high unmet medical needs because allogeneic stem cell transplantation is not an option for most patients, and JAK inhibitors are generally effective for only 2 to 3 years and do not delay disease progression. MF is characterized by dysplastic megakaryocytic hyperplasia and progression to fulminant disease, which is associated with progressively increasing marrow fibrosis. Despite evidence that the inflammatory milieu in MF contributes to disease progression, the specific factors that promote megakaryocyte growth are poorly understood. Here, we analyzed changes in the cytokine profiles of MF mouse models before and after the development of fibrosis, coupled with the analysis of bone marrow populations using single-cell RNA sequencing. We found high interleukin 13 (IL-13) levels in the bone marrow of MF mice. IL-13 promoted the growth of mutant megakaryocytes and induced surface expression of transforming growth factor β and collagen biosynthesis. Similarly, analysis of samples from patients with MF revealed elevated levels of IL-13 in the plasma and increased IL-13 receptor expression in marrow megakaryocytes. In vivo, IL-13 overexpression promoted disease progression, whereas reducing IL-13/IL-4 signaling reduced several features of the disease, including fibrosis. Finally, we observed an increase in the number of marrow T cells and mast cells, which are known sources of IL-13. Together, our data demonstrate that IL-13 is involved in disease progression in MF and that inhibition of the IL-13/IL-4 signaling pathway might serve as a novel therapeutic target to treat MF., (© 2022 by The American Society of Hematology.)

Clinical manifestations of severe COVID-19 include coagulopathies that are exacerbated by the formation of neutrophil extracellular traps (NETs). Here, we report that pulmonary lymphatic vessels, which traffic neutrophils and other immune cells to the lung-draining lymph node (LDLN), can also be blocked by fibrin clots in severe COVID-19. Immunostained tissue sections from COVID-19 decedents revealed widespread lymphatic clotting not only in the lung but also in the LDLN, where the extent of clotting correlated with the presence of abnormal, regressed, or missing germinal centers (GCs). It strongly correlated with the presence of intralymphatic NETs. In mice, tumor necrosis factor α induced intralymphatic fibrin clots; this could be inhibited by DNase I, which degrades NETs. In vitro, TNF-α induced lymphatic endothelial cell upregulation of ICAM-1 and CXCL8, among other neutrophil-recruiting factors, as well as thrombomodulin downregulation; in decedents, lymphatic clotting in LDLNs. In a separate cohort of hospitalized patients, serum levels of Myeloperoxidase-DNA (MPO-DNA, a NET marker) inversely correlated with antiviral antibody titers, but D-dimer levels, indicative of blood thrombosis, did not correlate with either. Patients with high MPO-DNA but low D-dimer levels generated poor antiviral antibody titers. This study introduces lymphatic coagulation in lungs and LDLNs as a clinical manifestation of severe COVID-19 and suggests the involvement of NETosis of lymphatic-trafficking neutrophils. It further suggests that lymphatic clotting may correlate with impaired formation or maintenance of GCs necessary for robust antiviral antibody responses, although further studies are needed to determine whether and how lymphatic coagulation affects adaptive immune responses., (© 2022 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Competing Interests: Juan AlbanEmployment: AbbVie (I)Leadership: AbbVie (I), SpringWorks Therapeutics (I) Adam DuVallConsulting or Advisory Role: Jazz PharmaceuticalsSpeakers' Bureau: Jazz Pharmaceuticals Sandeep GurbuxaniConsulting or Advisory Role: AbbViePatents, Royalties, Other Intellectual Property: Royalties from UpToDate for contributions to various topics Wendy StockHonoraria: AbbVie, PfizerConsulting or Advisory Role: Jazz Pharmaceuticals, Kite, a Gilead Company, Kura Oncology, GlaxoSmithKline, Morphosys, Pfizer, Servier, Deciphira, BEAm, Newave Pharmaceutical, AstraZeneca, Kronos Bio, Pluristem TherapeuticsPatents, Royalties, Other Intellectual Property: Royalties for a chapter in Up to DateTravel, Accommodations, Expenses: Pfizer Anand Ashwin PatelResearch Funding: Bristol Myers Squibb/Celgene (Inst), Servier (Inst), Pfizer (Inst)No other potential conflicts of interest were reported.

The influence of the microbiota on viral transmission and replication is well appreciated. However, its impact on retroviral pathogenesis outside of transmission/replication control remains unknown. Using murine leukemia virus (MuLV), we found that some commensal bacteria promoted the development of leukemia induced by this retrovirus. The promotion of leukemia development by commensals is due to suppression of the adaptive immune response through upregulation of several negative regulators of immunity. These negative regulators include Serpinb9b and Rnf128, which are associated with a poor prognosis of some spontaneous human cancers. Upregulation of Serpinb9b is mediated by sensing of bacteria by the NOD1/NOD2/RIPK2 pathway. This work describes a mechanism by which the microbiota enhances tumorigenesis within gut-distant organs and points at potential targets for cancer therapy., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

Importance: Treatment of newly diagnosed multiple myeloma (NDMM) with a quadruplet regimen consisting of a monoclonal antibody, proteasome inhibitor, immunomodulatory imide, and corticosteroid has been associated with improved progression-free survival (PFS) compared with triplet regimens. The optimal quadruplet combination, and whether this obviates the need for frontline autologous stem cell transplant (ASCT), remains unknown. We evaluated elotuzumab and weekly carfilzomib, lenalidomide, and dexamethasone (Elo-KRd) without ASCT in NDMM., Objective: To investigate the efficacy of Elo-KRd using a measurable residual disease (MRD)-adapted design in NDMM regardless of ASCT eligibility., Design, Setting, and Participants: This multicenter, single-arm, phase 2 study enrolled patients between July 2017 and February 2021. Median follow-up was 29 months., Interventions: Twelve to 24 cycles of Elo-KRd; consecutive MRD-negative results at 10-6 by next-generation sequencing (NGS) after cycles 8 (C8) and 12 determined the duration of Elo-KRd. This was followed by Elo-Rd (no carfilzomib) maintenance therapy until disease progression., Main Outcomes and Measures: The primary end point was the rate of stringent complete response (sCR) and/or MRD-negativity (10-5) after C8 Elo-KRd. Secondary end points included safety, rate of response, MRD status, PFS, and overall survival (OS). As an exploratory analysis, MRD was assessed using liquid chromatography mass spectrometry (MS) on peripheral blood samples., Results: Forty-six patients were enrolled (median age 62 years, 11 [24%] aged >70 years). Overall, 32 (70%) were White, 6 (13%) were Black, 3 (6%) were more than 1 race, and 5 (11%) were of unknown race. Thirty-three (72%) were men and 13 (28%) were women. High-risk cytogenetic abnormalities were present in 22 (48%) patients. The rate of sCR and/or MRD-negativity after C8 was 26 of 45 (58%), meeting the predefined statistical threshold for efficacy. Responses deepened over time, with the MRD-negativity (10-5) rate increasing to 70% and MS-negativity rate increasing to 65%; concordance between MRD by NGS and MS increased over time. The most common (>10%) grade 3 or 4 adverse events were lung and nonpulmonary infections (13% and 11%, respectively). There was 1 grade 5 myocardial infarction. The estimated 3-year PFS was 72% overall and 92% for patients with MRD-negativity (10-5) at C8., Conclusions and Relevance: An MRD-adapted design using elotuzumab and weekly KRd without ASCT showed a high rate of sCR and/or MRD-negativity and durable responses. This approach provides support for further evaluation of MRD-guided deescalation of therapy to decrease treatment exposure while sustaining deep responses., Trial Registration: ClinicalTrials.gov Identifier: NCT02969837.

Objectives: Glucose transporter 1 (GLUT1), a glucose transporter, is an abundant protein in erythrocytes with expression beginning early in erythropoiesis. We sought to evaluate the utility of GLUT1 immunohistochemistry (IHC) as a diagnostic marker for identifying erythroid differentiation in hematopoietic tissues, including neoplastic erythroid proliferations., Methods: A variety of benign and neoplastic bone marrow biopsy specimens containing variable proportions of erythroid precursors were selected (n = 46, including 36 cases of leukemia). GLUT1 IHC was performed using a commercially available polyclonal antibody. Each case was evaluated for staining of erythroid precursors, nonerythroid hematopoietic cells, and blasts. A GATA1/GLUT1 double stain was performed on one case to confirm coexpression of GLUT1 on early erythroid precursors. Staining was compared with other erythroid markers, including glycophorin C., Results: GLUT1 demonstrated strong membranous staining in erythroid precursors of all cases, which was restricted largely to the erythroid lineage. Of the 36 leukemia cases, all 6 cases of pure erythroid leukemia and both cases of therapy-related acute myeloid leukemia with erythroid differentiation showed positive GLUT1 staining in blasts. Otherwise, only lymphoblasts in B-lymphoblastic leukemia showed weak to moderate granular cytoplasmic staining (four of five cases)., Conclusions: GLUT1 IHC is a highly sensitive and relatively specific marker for erythroid lineage in benign and neoplastic bone marrow biopsy specimens., (© The Author(s) 2022. Published by Oxford University Press on behalf of American Society for Clinical Pathology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Approximately 20% of patients with myeloproliferative neoplasms (MPN) harbor mutations in the gene calreticulin (CALR), with 80% of those mutations classified as either type I or type II. While type II CALR-mutant proteins retain many of the Ca2+ binding sites present in the wild-type protein, type I CALR-mutant proteins lose these residues. The functional consequences of this differential loss of Ca2+ binding sites remain unexplored. Here, we show that the loss of Ca2+ binding residues in the type I mutant CALR protein directly impairs its Ca2+ binding ability, which in turn leads to depleted endoplasmic reticulum (ER) Ca2+ and subsequent activation of the IRE1α/XBP1 pathway of the unfolded protein response. Genetic or pharmacologic inhibition of IRE1α/XBP1 signaling induces cell death in type I mutant but not type II mutant or wild-type CALR-expressing cells, and abrogates type I mutant CALR-driven MPN disease progression in vivo., Significance: Current targeted therapies for CALR-mutated MPNs are not curative and fail to differentiate between type I- versus type II-driven disease. To improve treatment strategies, it is critical to identify CALR mutation type-specific vulnerabilities. Here we show that IRE1α/XBP1 represents a unique, targetable dependency specific to type I CALR-mutated MPNs. This article is highlighted in the In This Issue feature, p. 265., (©2022 American Association for Cancer Research.)

Normal T cells express high levels of B-cell lymphoma-2 (BCL2) protein, and data regarding BCL2 expression status and its diagnostic utility in T-cell lymphoma are scarce. We evaluated BCL2 expression in a series of mature T-cell lymphoproliferations (TCLs) including indolent and more recently recognized entities (follicular helper T-cell [TFH] lymphomas). Sixty-six neoplastic biopsies (60 patients) representing mature nodal, extranodal, and leukemia T-cell neoplasms were collected from three institutes (2 US and 1 Japan) and were compared with reactive T cells in 8 benign tissues/blood and 9 T cell-rich B-cell proliferations. BCL2 immunostaining was performed and scored based on intensity-weighted H-score (0-300). Next-generation sequencing (NGS; 5 cases), BCL2 gene sequencing, and real-time polymerase chain reaction (PCR; 3 cases) were conducted. Association of H-score with overall survival (using proportional hazards modeling) was assessed in nonleukemic TCLs. Most TCLs showed significantly downregulated median BCL2 H-score (125, range: 18-300) with the exception of T-cell prolymphocytic leukemia and hepatosplenic T-cell lymphoma, both of which showed uniform strong retention of BCL2 as did the 8 reactive tissues (median H-score: 280; p = 0.000). Notably all TFH lymphoma CD4 neoplastic T cells, subcutaneous panniculitis-like T-cell lymphoma, CD8 adipocyte-rimming T cells, and T-cell large lymphocyte leukemia with pathogenic STAT5B and TP53 mutation showed BCL2 downregulation. No BCL2 mutations were observed by NGS or sequencing with decreased BCL2 mRNA transcripts by real-time PCR. BCL2 downregulation is pervasive among many TCLs and unrelated to any mutations. There is utility for BCL2 immunostaining in some challenging situations as discussed in this article., (Copyright © 2022 Elsevier Inc. All rights reserved.)

BCR-ABL1 -like B-acute lymphoblastic leukemia (B-ALL) is a genetically heterogeneous group of high-risk B-ALL that benefits from targeted tyrosine kinase inhibitor (TKI) therapy. The incidence of this high-risk B-ALL is relatively low and screening with surrogate markers will be useful to identify patients for further genetic testing. Here we demonstrate that widely available MUC4 protein immunohistochemistry (IHC) is predictive of a BCR-ABL1 -like genotype for a subset of patients. Overall, MUC4 expression was observed in 36% (9/25) BCR-ABL1 -like, 43% (3/7) BCR-ABL1 + and 9% (2/22) B-ALL other cases ( p =.019 for BCR-ABL1 like and BCR-ABL1 + versus B-ALL others). Furthermore, 83% (5/6) of patients with ABL class fusions showed MUC4 expression when compared to 25% (4/16, p =.006) patients with JAK class fusions. Overall, the study demonstrates that MUC4 expression is highly specific (90.9%) for BCR-ABL1 + and BCR-ABL1 -like B-ALL with high sensitivity for cases with ABL class fusions.

Therapy-related myeloid neoplasms (t-MNs) are a complication of treatment with cytotoxic chemotherapy and/or radiation therapy. The majority of t-MNs show chromosomal abnormalities associated with myelodysplastic syndrome (MDS) or KMT2A rearrangements and are characterized by poor clinical outcomes. A small but substantial subset of patients have normal karyotype (NK) and their clinical characteristics and mutational profiles are not well studied. We retrospectively studied patients diagnosed with t-MN at three institutions and compared the mutational profile and survival data between t-MNs with NK and t-MNs with abnormal karyotype (AK). A total of 204 patients with t-MN were identified including 158 with AK and 46 with NK. NK t-MNs, compared to AK, were enriched for mutations in TET2 (p < 0.0001), NPM1 (p < 0.0001), ASXL1 (p = 0.0003), SRSF2 (p < 0.0001), RUNX1 (p = 0.0336) and STAG2 (p = 0.0099) and showed a significantly lower frequency of TP53 mutations (p < 0.0001). Overall survival (OS) was significantly lower in AK t-MNs as compared to NK cases (p = 0.0094). In our study, NK t-MNs showed a significantly better OS, a higher prevalence of MN-associated mutations and a lower frequency of TP53 mutations compared to their AK counterparts. The distinct clinical and mutational profile of NK t-MNs merits a separate classification., (© 2022 British Society for Haematology and John Wiley & Sons Ltd.)

Competing Interests: The authors declare no conflict of interest.

MECOM rearrangements are recurrent in myeloid neoplasms and associated with poor prognosis. However, only inv(3)(q21q26.2) and t(3;3)(q21;q26.2), the classic MECOM rearrangements resulting in RPN1-MECOM rearrangement with Mecom overexpression and GATA2 haploinsufficiency, define the distinct subtype of acute myeloid leukemia (AML), and serve as presumptive evidence for myelodysplastic syndrome based on the current World Health Organization classification. Myeloid neoplasms with nonclassic 3q26.2/MECOM rearrangements have been found to be clinically aggressive, but comparative analysis of clinicopathologic and genomic features is limited. We retrospectively studied cohorts of myeloid neoplasms with classic and nonclassic MECOM rearrangements. Cases with classic rearrangements consisted predominantly of AML, often with inv(3) or t(3;3) as the sole chromosome abnormality, whereas the group of nonclassic rearrangements included a variety of myeloid neoplasms, often with complex karyotype without TP53 mutations and similarly dismal overall survival. Immunohistochemistry revealed Mecom protein overexpression in both groups, but overexpression in cases with nonclassic rearrangements was mediated through a mechanism other than GATA2 distal enhancer involvement typical for classic rearrangement. Our results demonstrated that myeloid neoplasms with nonclassic 3q26.2/MECOM rearrangements encompass a diverse group of diseases with poor clinical outcome, overexpression of Mecom protein as a result of the nonclassic mechanism of MECOM activation., (© 2021 Wiley Periodicals LLC.)

Autopsies of patients who have died from COVID-19 have been crucial in delineating patterns of injury associated with SARS-CoV-2 infection. Despite their utility, comprehensive autopsy studies are somewhat lacking relative to the global burden of disease, and very few comprehensive studies contextualize the findings to other fatal viral infections. We developed a novel autopsy protocol in order to perform postmortem examinations on victims of COVID-19 and herein describe detailed clinical information, gross findings, and histologic features observed in the first 16 complete COVID-19 autopsies. We also critically evaluated the role of ancillary studies used to establish a diagnosis of COVID-19 at autopsy, including immunohistochemistry (IHC), in situ hybridization (ISH), and electron microscopy (EM). IHC and ISH targeting SARS-CoV-2 were comparable in terms of the location and number of infected cells in lung tissue; however, nonspecific staining of bacteria was seen occasionally with IHC. EM was unrevealing in blindly sampled tissues. We then compared the clinical and histologic features present in this series to six archival cases of fatal seasonal influenza and six archival cases of pandemic influenza from the fourth wave of the 'Spanish Flu' in the winter of 1920. In addition to routine histology, the inflammatory infiltrates in the lungs of COVID-19 and seasonal influenza victims were compared using quantitative IHC. Our results demonstrate that the clinical and histologic features of COVID-19 are similar to those seen in fatal cases of influenza, and the two diseases tend to overlap histologically. There was no significant difference in the composition of the inflammatory infiltrate in COVID-19 and influenza at sites of acute lung injury at the time of autopsy. Our study underscores the relatively nonspecific clinical features and pathologic changes shared between severe cases of COVID-19 and influenza, while also providing important caveats to ancillary methods of viral detection., (© 2021 The Authors. The Journal of Pathology: Clinical Research published by The Pathological Society of Great Britain and Ireland & John Wiley & Sons, Ltd.)

Although acute lymphoblastic leukemia (ALL) is most common in pediatric and adolescent and young adult (AYA) patients, 20% of cases are diagnosed in patients ≥ 55 years old. Use of intensive pediatric regimens in AYA populations has demonstrated excellent tolerability and significant improvements in event-free survival (EFS) and overall survival (OS). The backbone of pediatric regimens includes asparaginase and corticosteroids, both of which are associated with more toxicity in older patients and those with body mass index (BMI) ≥ 30 kg/m which leads to poor tolerance of these regimens. We tested the safety and efficacy of a dose-modified The Cancer and Leukemia Group B 10403 regimen using reduced doses of pegylated (PEG)-asparaginase (ASP) and corticosteroids (RD-10403) in 30 patients with Philadelphia-chromosome negative ALL who were ≥50-year-old and younger adults with significant metabolic or hepatic co-morbidities. The complete remission rate on day 28 was 77%, 3-year EFS was 54%, and estimated 3-year OS was 55%. Grade 3+ toxicity was noted in 40% of patients during induction, and induction-related mortality was 3%. Additional prospective evaluation of RD-10403 is merited to determine efficacy and safety of this regimen and to serve as a framework for chemoimmunotherapy combination therapy., Competing Interests: Anand Ashwin Patel, Sarah Monick, Adam S. DuVall, Sandeep Gurbuxani, and Satyajit Kosuri have no conflict of interest. Joseph Heng is honoraria from OncLive, while Emily Dworkin is honoraria from Abbvie. Benjamin A. Derman is in advisory board from Sanofi. Hongtao Liu did research funding from BMS and Karyopharm; is honoraria from Agios. Michael Thirman did research funding from Gilead Sciences, Pharmacyclics, Janssen, AbbVie, Merck, Syndax, TG Therapeutics, Tolero; is in advisory board from AstraZeneca, Celgene, Roche/Genentech, Pharmacyclics, Janssen, Abbvie. Lucy A. Godley is advisory board from Invitae, Inc; royalties from UpToDate. Olatoyosi Odenike did research funding from AstraZeneca, ABBVIE, astex, agios, incyte, janssen, NS‐Pharma, Oncotherapy Sciences, BMS; is honoraria/has ad board membership‐ ABBVIE, BMS, Celgene, Novartis, Taiho, PRA. Richard A. Larson has acted as a consultant or advisor to Amgen, Ariad/Takeda, Celgene/Bristol Myers Squibb, CVS/Caremark, Epizyme, MorphoSys, and Novartis, and has received clinical research support to his institution from Astellas, Celgene, Cellectis, Daiichi Sankyo, Forty Seven/Gilead, Novartis, Rafael Pharmaceuticals, and royalties from UpToDate. Wendy Stock is Honoraria from Abbvie, Jazz, Kite, Morphosys, Pfizer, Servier., (© 2021 The Authors. eJHaem published by British Society for Haematology and John Wiley & Sons Ltd.)

The myeloproliferative neoplasms (MPN) frequently progress to blast phase disease, an aggressive form of acute myeloid leukemia. To identify genes that suppress disease progression, we performed a focused CRISPR/Cas9 screen and discovered that depletion of LKB1/ Stk11 led to enhanced in vitro self-renewal of murine MPN cells. Deletion of Stk11 in a mouse MPN model caused rapid lethality with enhanced fibrosis, osteosclerosis, and an accumulation of immature cells in the bone marrow, as well as enhanced engraftment of primary human MPN cells in vivo . LKB1 loss was associated with increased mitochondrial reactive oxygen species and stabilization of HIF1α, and downregulation of LKB1 and increased levels of HIF1α were observed in human blast phase MPN specimens. Of note, we observed strong concordance of pathways that were enriched in murine MPN cells with LKB1 loss with those enriched in blast phase MPN patient specimens, supporting the conclusion that STK11 is a tumor suppressor in the MPNs. SIGNIFICANCE: Progression of the myeloproliferative neoplasms to acute myeloid leukemia occurs in a substantial number of cases, but the genetic basis has been unclear. We discovered that loss of LKB1/ STK11 leads to stabilization of HIF1a and promotes disease progression. This observation provides a potential therapeutic avenue for targeting progression. This article is highlighted in the In This Issue feature, p. 1307 ., (©2021 American Association for Cancer Research.)

In this phase 2 multicenter study, we evaluated the incorporation of autologous stem cell transplantation (ASCT) into a carfilzomib-lenalidomide-dexamethasone (KRd) regimen for patients with newly diagnosed multiple myeloma (NDMM). Transplant-eligible patients with NDMM received 4 cycles of KRd induction, ASCT, 4 cycles of KRd consolidation, and 10 cycles of KRd maintenance. The primary end point was rate of stringent complete response (sCR) after 8 cycles of KRd with a predefined threshold of ≥50% to support further study. Seventy-six patients were enrolled with a median age of 59 years (range, 40-76 years), and 35.5% had high-risk cytogenetics. The primary end point was met, with an sCR rate of 60% after 8 cycles. Depth of response improved over time. On intent-to-treat (ITT), the sCR rate reached 76%. The rate of minimal residual disease (MRD) negativity using modified ITT was 70% according to next-generation sequencing (<10-5 sensitivity). After median follow-up of 56 months, 5-year progression-free survival (PFS) and overall survival (OS) rates were 72% and 84% for ITT, 85% and 91% for MRD-negative patients, and 57% and 72% for patients with high-risk cytogenetics. For high-risk patients who were MRD negative, 5-year rates were 77% and 81%. Grade 3 to 4 adverse events included neutropenia (34%), lymphopenia (32%), infection (22%), and cardiac events (3%). There was no grade 3 to 4 peripheral neuropathy. Patients with NDMM treated with KRd with ASCT achieved high rates of sCR and MRD-negative disease at the end of KRd consolidation. Extended KRd maintenance after consolidation contributed to deepening of responses and likely to prolonged PFS and OS. Safety and tolerability were manageable. This trial was registered at www.clinicaltrials.gov as #NCT01816971., (© 2020 by The American Society of Hematology.)

Telomere biology disorders (TBDs) present heterogeneously, ranging from infantile bone marrow failure associated with very short telomeres to adult-onset interstitial lung disease (ILD) with normal telomere length. Yield of genetic testing and phenotypic spectra for TBDs caused by the expanding list of telomere genes in adults remain understudied. Thus, we screened adults aged ≥18 years with a personal and/or family history clustering hematologic disorders and/or ILD enrolled on The University of Chicago Inherited Hematologic Disorders Registry for causative variants in 13 TBD genes. Sixteen (10%) of 153 probands carried causative variants distributed among TERT (n = 6), TERC (n = 4), PARN (n = 5), or RTEL1 (n = 1), of which 19% were copy number variants. The highest yield (9 of 22 [41%]) was in families with mixed hematologic and ILD presentations, suggesting that ILD in hematology populations and hematologic abnormalities in ILD populations warrant TBD genetic testing. Four (3%) of 117 familial hematologic disorder families without ILD carried TBD variants, making TBD second to only DDX41 in frequency for genetic diagnoses in this population. Phenotypes of 17 carriers with heterozygous PARN variants included 4 (24%) with hematologic abnormalities, 67% with lymphocyte telomere lengths measured by flow cytometry and fluorescence in situ hybridization at or above the 10th percentile, and a high penetrance for ILD. Alternative etiologies for cytopenias and/or ILD such as autoimmune features were noted in multiple TBD families, emphasizing the need to maintain clinical suspicion for a TBD despite the presence of alternative explanations., (© 2020 by The American Society of Hematology.)