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BCR sequencing

Table S2 contains a summary of the B cell receptor sequencing data of lymphoma samples. It includes 1) an overview of the investigated samples, 2) a list of characteristics of the dominant clone of each lymphoma sample, 3) a list comparing the frequencies of V family usage in WT samples to the lymphoma frequency, 4) the frequencies of FR and CDR mutations in samples analyzed by full-length BCR sequencing.

Figures S1 - S8

A third of patients with diffuse large B-cell lymphoma (DLBCL) present with extranodal dissemination, which is associated with inferior clinical outcomes. MYD88L265P is a hallmark extranodal DLBCL mutation that supports lymphoma proliferation. Yet extranodal lymphomagenesis and the role of MYD88L265P in transformation remain mostly unknown. Here, we show that B cells expressing Myd88L252P (MYD88L265P murine equivalent) activate, proliferate, and differentiate with minimal T-cell costimulation. Additionally, Myd88L252P skewed B cells toward memory fate. Unexpectedly, the transcriptional and phenotypic profiles of B cells expressing Myd88L252P, or other extranodal lymphoma founder mutations, resembled those of CD11c+T-BET+ aged/autoimmune memory B cells (AiBC). AiBC-like cells progressively accumulated in animals prone to develop lymphomas, and ablation of T-BET, the AiBC master regulator, stripped mouse and human mutant B cells of their competitive fitness. By identifying a phenotypically defined prospective lymphoma precursor population and its dependencies, our findings pave the way for the early detection of premalignant states and targeted prophylactic interventions in high-risk patients.Significance:Extranodal lymphomas feature a very poor prognosis. The identification of phenotypically distinguishable prospective precursor cells represents a milestone in the pursuit of earlier diagnosis, patient stratification, and prophylactic interventions. Conceptually, we found that extranodal lymphomas and autoimmune disorders harness overlapping pathogenic trajectories, suggesting these B-cell disorders develop and evolve within a spectrum.See related commentary by Leveille et al. (Blood Cancer Discov 2023;4:8–11).This article is highlighted in the In This Issue feature, p. 1

Supplementary Table S1 - Differentially expressed genes and PAGE analysis in Myd88 L252P GCB

This file contains the Supplementary Figures S1 to S12.

Gating strategies, validation of results using alternative models or definitions, QC controls, etc.

Based on gene expression profiles, diffuse large B-cell lymphoma (DLBCL) is subdivided into germinal center B-cell–like (GCB) and activated B-cell–like (ABC) DLBCL. Two of the most common genomic aberrations in ABC-DLBCL are mutations in MYD88 as well as BCL2 copy-number gains. Here, we employ immune phenotyping, RNA sequencing, and whole-exome sequencing to characterize a Myd88- and BCL2-driven mouse model of ABC-DLBCL. We show that this model resembles features of human ABC-DLBCL. We further demonstrate an actionable dependence of our murine ABC-DLBCL model on BCL2. This BCL2 dependence was also detectable in human ABC-DLBCL cell lines. Moreover, human ABC-DLBCLs displayed increased PD-L1 expression compared with GCB-DLBCL. In vivo experiments in our ABC-DLBCL model showed that combined venetoclax and PD-1 blockade significantly increased the overall survival of lymphoma-bearing animals, indicating that this combination may be a viable option for selected human ABC-DLBCL cases harboring MYD88 and BCL2 aberrations.Significance:Oncogenic Myd88 and BCL2 cooperate in murine DLBCL lymphomagenesis. The resulting lymphomas display morphologic and transcriptomic features reminiscent of human ABC-DLBCL. Data derived from our Myd88/BCL2-driven autochthonous model demonstrate that combined BCL2 and PD-1 blockade displays substantial preclinical antilymphoma activity, providing preclinical proof-of-concept data, which pave the way for clinical translation.This article is highlighted in the In This Issue feature, p. 1

Genomic profiling revealed the identity of at least 5 subtypes of diffuse large B-cell lymphoma (DLBCL), including the MCD/C5 cluster characterized by aberrations in MYD88, BCL2, PRDM1, and/or SPIB. We generated mouse models harboring B cell–specific Prdm1 or Spib aberrations on the background of oncogenic Myd88 and Bcl2 lesions. We deployed whole-exome sequencing, transcriptome, flow-cytometry, and mass cytometry analyses to demonstrate that Prdm1- or Spib-altered lymphomas display molecular features consistent with prememory B cells and light-zone B cells, whereas lymphomas lacking these alterations were enriched for late light-zone and plasmablast-associated gene sets. Consistent with the phenotypic evidence for increased B cell receptor signaling activity in Prdm1-altered lymphomas, we demonstrate that combined BTK/BCL2 inhibition displays therapeutic activity in mice and in five of six relapsed/refractory DLBCL patients. Moreover, Prdm1-altered lymphomas were immunogenic upon transplantation into immuno-competent hosts, displayed an actionable PD-L1 surface expression, and were sensitive to antimurine-CD19-CAR-T cell therapy, in vivo.Significance:Relapsed/refractory DLBCL remains a major medical challenge, and most of these patients succumb to their disease. Here, we generated mouse models, faithfully recapitulating the biology of MYD88-driven human DLBCL. These models revealed robust preclinical activity of combined BTK/BCL2 inhibition. We confirmed activity of this regimen in pretreated non–GCB-DLBCL patients.See related commentary by Leveille et al., p. 8.This article is highlighted in the In This Issue feature, p. 1

A third of patients with diffuse large B-cell lymphoma (DLBCL) present with extranodal dissemination, which is associated with inferior clinical outcomes. MYD88L265P is a hallmark extranodal DLBCL mutation that supports lymphoma proliferation. Yet extranodal lymphomagenesis and the role of MYD88L265P in transformation remain mostly unknown. Here, we show that B cells expressing Myd88L252P (MYD88L265P murine equivalent) activate, proliferate, and differentiate with minimal T-cell costimulation. Additionally, Myd88L252P skewed B cells toward memory fate. Unexpectedly, the transcriptional and phenotypic profiles of B cells expressing Myd88L252P, or other extranodal lymphoma founder mutations, resembled those of CD11c+T-BET+ aged/autoimmune memory B cells (AiBC). AiBC-like cells progressively accumulated in animals prone to develop lymphomas, and ablation of T-BET, the AiBC master regulator, stripped mouse and human mutant B cells of their competitive fitness. By identifying a phenotypically defined prospective lymphoma precursor population and its dependencies, our findings pave the way for the early detection of premalignant states and targeted prophylactic interventions in high-risk patients. Significance: Extranodal lymphomas feature a very poor prognosis. The identification of phenotypically distinguishable prospective precursor cells represents a milestone in the pursuit of earlier diagnosis, patient stratification, and prophylactic interventions. Conceptually, we found that extranodal lymphomas and autoimmune disorders harness overlapping pathogenic trajectories, suggesting these B-cell disorders develop and evolve within a spectrum. See related commentary by Leveille et al. (Blood Cancer Discov 2023;4:8–11). This article is highlighted in the In This Issue feature, p. 1

Based on gene expression profiles, diffuse large B-cell lymphoma (DLBCL) is subdivided into germinal center B-cell–like (GCB) and activated B-cell–like (ABC) DLBCL. Two of the most common genomic aberrations in ABC-DLBCL are mutations in MYD88 as well as BCL2 copy-number gains. Here, we employ immune phenotyping, RNA sequencing, and whole-exome sequencing to characterize a Myd88- and BCL2-driven mouse model of ABC-DLBCL. We show that this model resembles features of human ABC-DLBCL. We further demonstrate an actionable dependence of our murine ABC-DLBCL model on BCL2. This BCL2 dependence was also detectable in human ABC-DLBCL cell lines. Moreover, human ABC-DLBCLs displayed increased PD-L1 expression compared with GCB-DLBCL. In vivo experiments in our ABC-DLBCL model showed that combined venetoclax and PD-1 blockade significantly increased the overall survival of lymphoma-bearing animals, indicating that this combination may be a viable option for selected human ABC-DLBCL cases harboring MYD88 and BCL2 aberrations. Significance: Oncogenic Myd88 and BCL2 cooperate in murine DLBCL lymphomagenesis. The resulting lymphomas display morphologic and transcriptomic features reminiscent of human ABC-DLBCL. Data derived from our Myd88/BCL2-driven autochthonous model demonstrate that combined BCL2 and PD-1 blockade displays substantial preclinical antilymphoma activity, providing preclinical proof-of-concept data, which pave the way for clinical translation. This article is highlighted in the In This Issue feature, p. 1

Genomic profiling revealed the identity of at least 5 subtypes of diffuse large B-cell lymphoma (DLBCL), including the MCD/C5 cluster characterized by aberrations in MYD88, BCL2, PRDM1, and/or SPIB. We generated mouse models harboring B cell–specific Prdm1 or Spib aberrations on the background of oncogenic Myd88 and Bcl2 lesions. We deployed whole-exome sequencing, transcriptome, flow-cytometry, and mass cytometry analyses to demonstrate that Prdm1- or Spib-altered lymphomas display molecular features consistent with prememory B cells and light-zone B cells, whereas lymphomas lacking these alterations were enriched for late light-zone and plasmablast-associated gene sets. Consistent with the phenotypic evidence for increased B cell receptor signaling activity in Prdm1-altered lymphomas, we demonstrate that combined BTK/BCL2 inhibition displays therapeutic activity in mice and in five of six relapsed/refractory DLBCL patients. Moreover, Prdm1-altered lymphomas were immunogenic upon transplantation into immuno-competent hosts, displayed an actionable PD-L1 surface expression, and were sensitive to antimurine-CD19-CAR-T cell therapy, in vivo. Significance: Relapsed/refractory DLBCL remains a major medical challenge, and most of these patients succumb to their disease. Here, we generated mouse models, faithfully recapitulating the biology of MYD88-driven human DLBCL. These models revealed robust preclinical activity of combined BTK/BCL2 inhibition. We confirmed activity of this regimen in pretreated non–GCB-DLBCL patients. See related commentary by Leveille et al., p. 8. This article is highlighted in the In This Issue feature, p. 1

Introduction: The CLL2-BCG trial is a prospective, open-label, multicenter phase-II study based on the "sequential triple-T" (tailored, targeted, total eradication of CLL) concept proposed earlier [Hallek M., Blood 2013; 122(23): 3723-34]. This concept consists of sequentially applied combinations of targeted agents and aims for achieving undetectable minimal residual disease (MRD). It uses a sequential application of bendamustine (Ben) for debulking, followed by obinutuzumab (Obi) plus idelalisib (Ide) as induction and maintenance therapy for an all-comer population of physically fit and unfit, treatment-naïve (t-n) and relapsed/refractory (r/r) CLL patients (pts) irrespective of high-risk genetic markers. Methods: Pts with an absolute lymphocyte count ≥ 25.000/µl and/or lymph nodes ≥ 5 cm were to receive 2 cycles of Ben as debulking (70 mg/m² d1&2 q28 d), unless contraindicated. In the induction phase Obi 1000 mg was administered on d 1, 8 and 15 of cycle 1 and d1 of cycles 2-6; Ide was added in cycle 2 (150 mg twice daily). In the maintenance phase, daily dosing of Ide was continued and Obi was administered every 3 months until achieving a MRD-negative complete response or for up to 24 months. The primary endpoint was the overall response rate (ORR) at the end of induction therapy, secondary endpoints included MRD assessment, safety and survival. Due to an increased incidence of opportunistic infections in other Ide trials, amendment 2 in March 2016 limited the recruitment to r/r CLL pts with high-risk features such as presence of a deletion 17p/TP53 mutation and/or ineligibility for ibrutinib treatment (refractoriness, intolerance or contraindications). Slow enrolment led to recruitment stop in September 2019. Results: Between May 2015 and September 2019, 48 pts were enrolled. Sixteen pts were t-n and 32 had r/r CLL with a median of 2 prior lines (range: 1-10); most common were BR and FCR, 6 pts each had received ibrutinib and venetoclax containing therapies. Median age was 66 (range 41-83) years, median CIRS score was 2 (0-13). Twenty-three pts (48%) were defined unfit by a CIRS score >6 (7 pts) and/or an impaired renal function with a Creatinine Clearance Thirty-eight patients (79%, 16 t-n and 22r/r) received Ben debulking. However, 8 pts never started the induction phase due to protocol amendment 2. Forty pts (10 t-n, 30 r/r) received induction treatment (FAS [full analysis set]), 33 completed the full 6 cycles (PP [per protocol] collective). Twenty-seven (7 t-n, 20 r/r) continued in a maintenance phase. At the end of induction, 32 of 40 pts (FAS) and 28 of 33 pts with 6 induction cycles (PP) responded (ORR 80% and 85%, respectively); undetectable MRD levels ( As of June 8th 2020, 603 adverse events (AEs) were reported in the entire cohort; 313 (52%) were related to study drug and 127 (21%) were serious adverse events. 286 (47%) occurred in the induction treatment (see table 1). Of these, 69 (24%) were CTC grade 3 and 18 (6%) CTC grade 4, 4 had a fatal outcome. Most common AEs in the induction were infusion-related reactions, neutropenia, thrombocytopenia, anemia, nasopharyngitis, headache, and fatigue [Table 2]. Summary/Conclusion: Sequential treatment with Ben debulking, followed by Obi and Ide induction and maintenance achieved responses and even undetectable MRD levels in CLL patients with high-risk disease and extensive prior therapy. However, the study also confirmed the known toxicities of Ide. In light of the current, alternative therapeutic options, the BCG regimen reported here should be used with caution, but represents an alternative treatment option if ibrutinib and venetoclax have failed. Disclosures Cramer: Gilead: Other: travel support, Research Funding; F. Hoffmann-LaRoche: Honoraria, Other: travel support, Research Funding; Acerta: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; AstraZeneca: Consultancy, Honoraria, Other: travel support, Research Funding; Beigene: Research Funding; AbbVie: Honoraria, Other: travel support; Novartis: Consultancy, Research Funding; Janssen-Cilag: Consultancy, Honoraria, Other: travel support, Research Funding. Von Tresckow:Celgene: Other: travel grants; AbbVie: Honoraria; Janssen-Cilag: Honoraria, Other: travel grants, Research Funding; F. Hoffmann-LaRoche: Honoraria, Other: travel grants, Research Funding. Fink:AbbVie: Other: travel grants; Janssen: Honoraria; Celgene: Research Funding. Tausch:Janssen-Cilag: Consultancy, Honoraria, Research Funding; Roche: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding. Knauf:Janssen-Cilag: Honoraria; AbbVie: Consultancy, Honoraria; AMGEN: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Mundipharma: Honoraria. Al-Sawaf:BeiGene: Research Funding; AbbVie: Consultancy, Honoraria, Other: personal fees, Research Funding; Roche: Consultancy, Honoraria, Other: personal fees, Research Funding; Gilead: Consultancy, Honoraria, Other: personal fees; Janssen: Consultancy, Honoraria, Other: personal fees, Research Funding; AstraZeneca: Consultancy, Honoraria, Other: personal fees. Langerbeins:AbbVie: Honoraria, Other: travel grants, Research Funding; F. Hoffmann-LaRoche: Honoraria, Other: travel grants, Research Funding; Janssen-Cilag: Honoraria, Other: travel grants, Research Funding; Mundipharma: Honoraria, Other: travel grants, Research Funding. Fischer:F. Hoffmann-La Roche: Honoraria, Other: travel grants; AbbVie: Honoraria. Kreuzer:Hoffmann-La Roche: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria, Research Funding; Janssen-Cilag: Consultancy, Honoraria, Research Funding; Mundipharma: Consultancy, Honoraria, Research Funding. Ritgen:Gilead: Other: travel grants; BMS: Consultancy, Honoraria, Other: travel grants; F. Hoffman-La Roche: Consultancy, Honoraria, Other: travel grants, Research Funding; Pfizer: Consultancy, Honoraria. Kneba:AbbVie: Consultancy, Honoraria, Other: travel support, Research Funding; F. Hoffmann-LaRoche: Consultancy, Honoraria, Other: travel support, Research Funding; Gilead: Consultancy, Honoraria, Other: travel support, Research Funding; Janssen-Cilag: Consultancy, Honoraria, Other: travel support, Research Funding; Mundipharma: Consultancy, Honoraria, Other: travel support, Research Funding. Wendtner:Mundipharma: Consultancy, Honoraria, Other: travel support, Research Funding; Pharmacyclics: Consultancy, Honoraria, Other: travel support, Research Funding; AbbVie: Consultancy, Honoraria, Other: travel support, Research Funding; Gilead: Consultancy, Honoraria, Other: travel support, Research Funding; Hoffmann-LaRoche: Consultancy, Honoraria, Other: travel support, Research Funding; Genentech: Consultancy, Honoraria, Other: travel support, Research Funding; Janssen-Cilag: Consultancy, Honoraria, Other: travel support, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Other: travel support, Research Funding. Stilgenbauer:Pharmacyclics: Consultancy, Honoraria, Other, Research Funding; Novartis: Consultancy, Honoraria, Other, Research Funding; Mundipharma: Consultancy, Honoraria, Other, Research Funding; Janssen-Cilag: Consultancy, Honoraria, Other: travel support, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Other: travel support, Research Funding; Gilead: Consultancy, Honoraria, Other: travel support, Research Funding; Genzyme: Consultancy, Honoraria, Other: travel support, Research Funding; Genentech: Consultancy, Honoraria, Other: travel support, Research Funding; F. Hoffmann-LaRoche: Consultancy, Honoraria, Other: travel support, Research Funding; Celgene: Consultancy, Honoraria, Other: travel support, Research Funding; Boehringer-Ingelheim: Consultancy, Honoraria, Other: travel support, Research Funding; Amgen: Consultancy, Honoraria, Other: travel support, Research Funding; AbbVie: Consultancy, Honoraria, Other: travel support, Research Funding. Eichhorst:Janssen-Cilag: Consultancy, Honoraria, Other: travel support, Research Funding; Celgene: Consultancy, Honoraria, Other: travel support, Research Funding; Novartis: Consultancy, Honoraria, Other: travel support, Research Funding; ArQule: Consultancy, Honoraria, Other: travel support, Research Funding; BeiGene: Consultancy, Honoraria, Other: travel support, Research Funding; Gilead: Consultancy, Honoraria, Other: travel support, Research Funding; AstraZeneca: Consultancy, Honoraria, Other: travel support, Research Funding; Oxford Biomedica: Consultancy, Honoraria, Other: travel support, Research Funding; F. Hoffmann-LaRoche: Consultancy, Honoraria, Other: travel support, Research Funding; AbbVie: Consultancy, Honoraria, Other: travel support, Research Funding. Hallek:F. Hoffmann-LaRoche: Consultancy, Honoraria, Research Funding; Gilead: Consultancy, Honoraria, Research Funding; Mundipharma: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; AbbVie: Consultancy, Honoraria, Research Funding.

Sexual and gender minority (SGM) medical students and physicians are exposed to bias in professional contexts. One strategy for promoting SGM visibility and inclusion within medicine is the development of institutional OutLists, which are online, opt-in lists of SGM-identified individuals affiliated with an academic institution. We present the first quantitative evaluation of publicly accessible OutLists at medical institutions in the United States, Canada, and Europe. Nineteen OutLists were identified in the United States; no OutLists were identified in other countries. All OutLists in the United States were identified at allopathic institutions with no institutional religious affiliation. Clinicians in high-prestige specialties and more senior clinicians were underrepresented on OutLists. A state-level measure of SGM equality predicted presence of OutLists within the state (odds ratio 1.429

About 100 years ago, the first antibiotic drug was introduced into health care. Since then, antibiotics have made an outstanding impact on human medicine. However, our society increasingly suffers from collateral damage exerted by these highly effective drugs. The rise of resistant pathogen strains, combined with a reduction of microbiota diversity upon antibiotic treatment, has become a significant obstacle in the fight against invasive infections worldwide. Alternative and complementary strategies to classical “Fleming antibiotics” comprise microbiota-based treatments such as fecal microbiota transfer and administration of probiotics, live-biotherapeutics, prebiotics, and postbiotics. Other promising interventions, whose efficacy may also be influenced by the human microbiota, are phages and vaccines. They will facilitate antimicrobial stewardship, to date the only globally applied antibiotic resistance mitigation strategy. In this review, we present the available evidence on these nontraditional interventions, highlight their interaction with the human microbiota, and discuss their clinical applicability., Gut Microbes, 13 (1), ISSN:1949-0976, ISSN:1949-0984

Fifty-one of 189 evaluable patients from 3 prospective phase 2 trials evaluating a sequential targeted treatment had high-risk chronic lymphocytic leukemia (CLL) with a 17p deletion, TP53 mutation, or both. Twenty-seven patients started treatment with bendamustine debulking before induction and maintenance treatment, which was ibrutinib/ofatumumab (IO) in 21 patients, ibrutinib/obinutuzumab (IG) in 13, and venetoclax/obinutuzumab (AG) in 17. The primary end point was overall response rate after 8 months of induction treatment, which was 81%, 100%, and 94% for IO, IG, and AG, respectively. Minimal residual disease (MRD) was undetectable (uMRD) in peripheral blood (

Autonomous migration is a central characteristic of immune cells, and changes in this function have been correlated to the progression and severity of diseases. Hence, the identification of pathologically altered leukocyte migration patterns might be a promising approach for disease surveillance and prognostic scoring. However, because of the lack of standardized and robust assays, migration patterns have not been clinically exploited so far. In this study, we introduce an easy-to-use and cross-laboratory, standardized two-dimensional migration assay for neutrophil granulocytes from peripheral blood. By combining time-lapse video microscopy and automated cell tracking, we calculated the average migration of neutrophils from 111 individual participants of the German Heinz Nixdorf Recall MultiGeneration study under steady-state, formyl-methionyl-leucyl-phenylalanine–, CXCL1-, and CXCL8-stimulated conditions. Comparable values were obtained in an independent laboratory from a cohort in Belgium, demonstrating the robustness and transferability of the assay. In a double-blinded retrospective clinical analysis, we found that neutrophil migration strongly correlated with the Revised International Prognostic Scoring System scoring and risk category of myelodysplastic syndrome (MDS) patients. In fact, patients suffering from high-risk subtypes MDS with excess blasts I or II displayed highly significantly reduced neutrophil migration. Hence, the determination of neutrophil migration patterns might represent a useful tool in the surveillance of MDS. Taken together, we suggest that standardized migration assays of neutrophils and other leukocyte subtypes might be broadly applicable as prognostic and surveillance tools for MDS and potentially for other diseases.

Diffuse large B cell lymphoma (DLBCL) is the most common lymphoid malignancy in adults. Both biologically and clinically, DLBCL represents a highly heterogeneous disease. DLBCL has been subdivided into germinal center B cell (GCB)-like and activated B cell (ABC)-like DLBCL, on the basis of gene expression profiling, which separates DLBCL according to the presumed cell of origin (COO). This COO-based classifier distinguishes sub-entities displaying distinct biological features, pathogenesis and clinical response to frontline therapy. In addition to this classic transcriptome-based stratifier, recent genomic analyses of human DLBCL samples led to the discovery of partially overlapping genetically-defined DLBCL subsets. A study by Schmitz et al. employed a supervised clustering approach, allowing the classification of ~50% of the cases into four genetically-defined DLBCL subtypes, one of which is being characterized by co-occurring MYD88- and CD79B mutations as well as high expression of BCL2 (termed MCD). In a second approach by Chapuy et al., patient samples were clustered in an unsupervised manner. Also in this study, a cluster with recurrent mutations in MYD88 (specifically p.L265P) and CD79B, as well as gains of 18q (the location of BCL2) was identified (termed C5). We previously reported the formation of B cell lymphoma in mice that were engineered to express Myd88 p.L252P in combination with overexpression of BCL2 (Myd88 p.L252P/wt;R26 LSL.BCL2/wt;Cd19 Cre/wt, abbr. MBC) in a B cell-specific manner. While the developing lesions display many features of human ABC DLBCL, their B220 -/CD138 + immunophenotype reflects plasmablastic characteristics. To refine this mouse model, we incorporated additional C5/MCD lesions by engineering a B cell-specific loss of Prmd1 or Spib overexpression generating Prdm1 fl/fl;Myd88 p.L252P/wt;R26 LSL.BCL2/wt;Cd19 Cre/wt (PPMBC) and Myd88 p.L252P/wt;R26 LSL.BCL2/LSL.Spib;Cd19 Cre/wt (SMBC) compound animals. Both, the B cell-specific loss of Prdm1 and Spib overexpression on the MBC background resulted in a marked reduction of CD138 + cells in the spleens of 10 weeks old animals compared to control (Fig. 1A), accompanied by a decrease in serum immunoglobulins, indicative of a plasma cell differentiation block and in agreement with the reported function of PRMD1 and SPIB as transcription factors regulating plasma cell differentiation. Both PPMBC and SMBC mice developed lymphoma significantly earlier than MBC animals. These tumors largely displayed a B220 +/CD138 - immunophenotype. As transcriptional profiling is the gold standard for differentiation between GCB and ABC DLBCL, we generated germinal center- and activated blood B cell gene sets from healthy donors. We then performed gene set enrichment analyses between SMBC/PPMBC tumors and either MBC or Kmt2d fl/fl;VavP-Bcl2;Cɣ1 Cre/wt (KBC) lymphomas, the latter being reminiscent of human GCB DLBCL. While both PPMBC and SMBC samples were enriched for GCB gene signatures when compared to MBC, they enriched for ABC gene sets in comparison to KBC, potentially suggesting a developmental stage between KBC and MBC lesions (Fig. 1B). We next aimed to employ our PPMBC model of C5 DLBCL as a pre-clinical tool, in order to derive therapeutic approaches for this disease. In this regard, we note BCL2 has emerged as a potential therapeutic target in DLBCL. The BCL2 inhibitor venetoclax produces response rates of ~18% in relapsed/refractory DLBCL (Davids et al., 2017). Similarly, in a phase I/II clinical trial involving 80 patients with relapsed/refractory DLBCL, ibrutinib induced complete or partial remissions in 37% of ABC-DLBCL patients, but in only 5% GCB-DLBCL patients (Wilson et al., 2015). Building on these observations, we asked whether single agent or combined venetoclax and ibrutinib treatment might display pre-clinical activity in the PPMBC setting. Indeed, combination treatment with ibrutinib and venetoclax resulted in a significant survival benefit compared to single compound or untreated animals (Fig. 1C). Given this preclinical activity, we treated 6 relapsed/refractory (r/r) non-GCB DLBCL patients (determined by Hans algorithm) in an off-label setting and observed tumor shrinkage in 5 of 6 patients (Fig. 1D). Thus, our clinical data corroborate our preclinical observations and suggest that combined venetoclax and ibrutinib may display clinical activity in a subset of r/r non-GCB DLBCL. Figure 1 Figure 1. Disclosures Hallek: Roche: Honoraria, Speakers Bureau; Gilead: Honoraria, Speakers Bureau; Mundipharma: Honoraria, Speakers Bureau; Janssen: Honoraria, Speakers Bureau; Celgene: Honoraria, Speakers Bureau; Pharmacyclics: Honoraria, Speakers Bureau. Calado: Myricx Pharma: Consultancy, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company, Patents & Royalties: Cancer Treatments. WO patent WO 2020/128475 A1 (2020). Pasqualucci: Sanofi: Research Funding; Astra Zeneca: Research Funding. von Tresckow: Amgen: Consultancy, Honoraria; AbbVie: Other: congress and travel support; Pentixafarm: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; BMS-Celgene: Consultancy, Honoraria, Other: congress and travel support; MSD: Consultancy, Honoraria, Other: congress and travel support, Research Funding; Novartis: Consultancy, Honoraria, Other: congress and travel support, Research Funding; AstraZeneca: Honoraria, Other: congress and travel support; Kite-Gilead: Consultancy, Honoraria; Roche: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Other, Research Funding. Chapuy: Gilead: Honoraria; BMS: Honoraria; Regeneron: Consultancy; Gilead Sciences: Research Funding; Astra Zeneca: Honoraria. Reinhardt: CDL Therapeutics: Current holder of individual stocks in a privately-held company; Gilead: Research Funding; Merck: Consultancy; Vertex: Consultancy; AstraZeneca: Consultancy; Abbvie: Consultancy. OffLabel Disclosure: Treatment of DLBCL patients with ibrutinib and venetoclax.

Vaccination is one of the most useful preventive interventions in healthcare. The purpose of our study was to gain overview of the opinions, knowledge, and engagement in vaccination practices among medical students (MS) and junior doctors (JD) in Europe. The survey was distributed from March 2016 until August 2016 via the e-mail and social media of the European Medical Students’ Association. In total, 1821 responses from MS and JD from 34 countries in the European region were analysed. The majority of respondents agreed that vaccines are useful (98.7%) and effective (97.2%). Although the necessity of revaccination was supported by 99.2%, only 68.0% of the respondents went through with it. Even though the potential benefit of the flu vaccination seems to be acknowledged by our participants, only 22.1% of MS and JD declared getting the flu shot every or every other season. MS and JD were in favour of specific mandatory vaccination for medical staff (86.0%) and medical students (82.7%). Furthermore, we analysed the self-reported vaccination coverage of our participants regarding 19 vaccines. Of the respondents, 89.5% claimed to provide advice about vaccination to their friends and family. In conclusion, European MS and JD have a very positive attitude towards vaccination. However, their behaviour and knowledge demonstrate certain gaps which should be further addressed in medical education.

We determined the 10-year progression rate of light chain monoclonal gammopathy of undetermined significance (LCMGUS) and investigated potential associations with cancer utilizing the German population-based Heinz Nixdorf Recall Study. The Heinz Nixdorf Recall Study comprises 4814 men and women aged 45–75 years. Serum samples from baseline (2000–2003) and five-year (2006–2008) and 10-year (2011–2015) follow-up examinations were screened for monoclonal free light chains (FLC). LCMGUS was defined as abnormal FLC ratio, increase of involved FLC with complete loss of immunoglobulin heavy chain, and absence of a history of lymphoproliferative disease (LPD). Seventy-five individuals with LCMGUS were identified across all three evaluation time points (median age 64 years; 43 (57%) male; FLCR > 1.65 65 (87%); FLCR ≤ 0.65 10 (13%)). After a median observation time of 11.5 years, none of the LCMGUS cases had progressed to overt LPD; in particular, we did not observe incident light chain multiple myeloma. On serial analysis 17/31 (55%), LCMGUS could not be confirmed and disappearance of the monoclonal protein was associated with low concentrations of the involved FLC. Individuals with LCMGUS had a 1.5-fold increased risk of cancer but did not show differences in overall survival or renal function as compared to individuals with normal FLC. In conclusion, LCMGUS represents a relatively benign condition with a high disappearance rate of the monoclonal protein on longitudinal analysis and normal overall survival at least in the population-based setting.

Acute myeloid leukemia (AML) develops by the acquisition of genomic alterations which initiate different pathways leading to full-blown malignancy. The type of genomic driver alteration governs AML biology and clinical disease course. Translocations involving the core-binding factor (CBF) complex such as t(8:21) and inv(16) represent distinct subgroups of AML genomic drivers. However, additional factors promoting CBF AML leukemogenesis remain largely unknown. Due to the hypoxic nature of the bone marrow the activation of the ubiquitous hypoxia-sensing pathway via HIF-1a might promote CBF leukemogenesis. Nevertheless, in different AML models HIF proteins were recently considered as oncogenic drivers and also as tumor suppressors. Therefore, we here aimed to clarify the role of HIF-1a in CBF AML. Initially, we investigated the impact of hypoxia-sensing pathway activation on the growth of the CBF AML cell lines Kasumi-1 [t(8:21)] and ME-1 [inv(16)]. Kasumi-1 cells showed increased growth after 24 as well as 48 hours at 3% compared to 21% oxygen conditions. In contrast, ME-1 cellular growth was not altered by hypoxic culture conditions. Next, we genetically modified the HIF-1a pathway in the CBF AML leukemogenesis context with a previously established conditional inv(16) mouse model (Cbfb+/56M). These mice express the Cbfbeta-SMMHC oncoprotein upon Cre-mediated recombination. In preliminary studies we could show neither vav-iCre mediated Hif-1a gain- nor loss-of-function altered steady-state hematopoiesis, which was recently confirmed by others (Milica Vukovic et al., Blood 2016). We proceeded by crossing conditional inv(16) with conditional mice overexpressing a HIF-1a variant (LSL-HIF1dPA) being insensitive to oxygen-dependent degradation. The conditional inv(16) and HIF1dPA alleles were simultaneously activated using the ubiquitous hematopoietic vav-iCre transgene. Strikingly, we observed accelerated leukemia development in inv16;HIF1dPA mice compared to inv(16) mice without genetic HIF-1a pathway alterations (median survival 68 vs. 116 days; Figure 1). In a complementary approach we crossed the vavi-Cre conditional inv(16) system into a conditional Hif-1a knock-out (KO) background [inv(16);Hif-1aKO mice]. Here we observed significantly delayed leukemia onset in inv(16);Hif-1aKO mice compared to inv(16) control mice (median survival 223 vs. 116 days; Figure 1). The gross leukemic phenotype with high peripheral leukocyte count, splenomegaly and liver infiltration did not differ between the groups. Finally, we analyzed deletion of the conditional Hif-1aKO allele of leukemic inv(16);Hif-1aKO mice and observed complete recombination resulting in a Hif-1a null constellation. Thus, AML in inv(16);Hif-1aKO mice did not develop from clones which evaded vav-iCre mediated Hif-1a deletion. In conclusion, HIF-1a represents a critical factor promoting murine inv(16) leukemogenesis and it will be worthwhile studying the impact of genetic or pharmacologic HIF-1a alteration in established inv(16) leukemia. Figure 1 Kaplan-Meier curves of leukemia-free survival in control [Cre-negative littermates; n=55], inv(16) [n=31], inv(16);HIF1dPA [n=17] and inv(16);Hif-1aKO [n=18] mice. Figure 1. Kaplan-Meier curves of leukemia-free survival in control [Cre-negative littermates; n=55], inv(16) [n=31], inv(16);HIF1dPA [n=17] and inv(16);Hif-1aKO [n=18] mice. Disclosures Dührsen: Roche: Honoraria, Research Funding; Alexion Pharmaceuticals: Honoraria, Research Funding; Amgen: Honoraria, Research Funding. Göthert:Proteros: Consultancy; Ariad Pharmaceuticals: Consultancy; Bristol-Myers Squibb: Honoraria; Novartis: Honoraria.