Inferior survival in high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements is not associated with MYC/IG gene rearrangements

Advances in the Classification of Aggressive B-cell Lymphomas

Aggressive B-cell lymphomas are a biologically and clinically very heterogeneous group of tumors that may be related to different stages of B-cell differentiation development. This review aims to summarize recent advances in the understanding of these tumors with a focus on the practical approach to the diagnosis of these entities. We analyze the defining characteristics of the different subtypes of aggressive B-cell lymphomas, including nodal and extranodal diffuse large B-cell lymphoma, virus-associated lymphomas, terminally differentiated B-cell lymphomas, high-grade B-cell lymphomas, and Burkitt lymphoma. This review particularly explores the integration of morphologic, immunophenotypic, and genetic data that refine diagnostic accuracy and prognostic stratification, underscoring the necessity for a standardized approach in clinical practice. By synthesizing current knowledge, this review aims to enhance the understanding of aggressive B-cell lymphomas within the context of the evolving classification system, paving the way for future research and clinical advancements.

How I diagnose high-grade B-cell lymphoma

OBJECTIVES

High-grade B-cell lymphoma (HGBL), introduced in the 2016 World Health Organization (WHO) revised fourth edition classification, included cases defined by MYC and BCL2 and/or BCL6 rearrangements or by high-grade morphology. Diagnostic criteria and nomenclature for these lymphomas were refined in the 2022 WHO fifth edition (WHO-5) classification and International Consensus Classification (ICC). This review describes our approach to the diagnosis of HGBL.

METHODS

Two cases are presented illustrating how we diagnose HGBL, including 1 case harboring MYC and BCL6 rearrangements and a second showing TdT expression in an HGBL with MYC and BCL2 rearrangements. The ways in which these cases are distinguished from other lymphomas with high-grade features and the appropriate nomenclature using WHO-5 and ICC classifications are emphasized.

RESULTS

An HGBL diagnosis requires integration of morphology, immunophenotype, and genetics and exclusion of other lymphomas with high-grade morphology, including Burkitt lymphoma, B-lymphoblastic leukemia/lymphoma (B-LBL/ALL), and blastoid mantle cell lymphoma. A diagnosis of HGBL/large B-cell lymphoma with 11q aberration should also be considered in certain patient populations.

CONCLUSIONS

High-grade B-cell lymphomas are subclassified based on morphologic and genetic features. There are differences in the nomenclature and definition of these lymphomas in the WHO-5 and ICC classifications. Distinguishing HGBLs from other mature B-cell lymphomas and B-LBL/ALL is critical so that patients receive appropriate treatment.

CNS relapse in high-grade B-cell lymphoma with MYC and BCL2 rearrangements and dark-zone signature-expressing DLBCL

ABSTRACT

High-grade B-cell lymphoma with MYC and BCL2 rearrangements (HGBCL-DH-BCL2), or "double-hit lymphoma," has been associated with a high risk of central nervous system (CNS) relapse. However, historic estimates are impacted by selection bias. We report CNS relapse rates associated with HGBCL-DH-BCL2 from a population-based cohort with complete fluorescence in situ hybridization testing, as well as diffuse large B-cell lymphoma morphology (DLBCL) tumors expressing the dark-zone gene expression signature (DZsig), which was originally derived from HGBCL-DH-BCL2. The 2-year CNS relapse risk in HGBCL-DH-BCL2 was 6.8%. CNS relapses were early, predominantly leptomeningeal (73%), and co-occurred with systemic relapse (64%). High-risk CNS International Prognostic Index (CNS-IPI) and concordant bone marrow involvement were associated with an elevated CNS relapse risk in HGBCL-DH-BCL2. The "refined cell-of-origin" classification assigned 20% of DLBCL morphology tumors with germinal center B-cell-like phenotype (GCB-DLBCL) into a distinct subgroup based on DZsig expression (DZsig+). CNS relapse risk in DZsig+ (2 year: 6.4%) was independent of HGBCL-DH-BCL2 status and was further stratified by the CNS-IPI. CNS relapse in DZsig-negative GCB-DLBCL was rare (2-year risk, 1.4%; P = .04 vs DZsig+) and exclusively parenchymal. Altogether, the CNS relapse risk in HGBCL-DH-BCL2 is lower than previously reported, and DZsig refines risk stratification in GCB-DLBCL.

CODOX-M/IVAC-R versus DA-EPOCH-R in double-hit/triple-hit lymphoma patients aged 60 years or under

Intensified chemoimmunotherapy regimens are often used in young patients with double-hit and triple-hit lymphoma (DHL/ THL) despite no survival benefit compared to R-CHOP. Favorable retrospective reports on the application of CODOX-M/IVAC-R are subject to selection bias as only young fit patients can tolerate this treatment. We conducted a retrospective analysis to investigate outcome differences between CODOX-M/IVAC-R and DA-EPOCH-R in DHL/THL patients aged 60 years or younger. One hundred and thirteen patients were identified; CODOX-M/IVAC-R (N=49) and DA-EPOCH-R (N=64). Eighty percent (39/49) achieved complete (CR) after completing CODOX-M/IVAC-R compared to 58% (37/64) with DA-EPOCH-R. The median follow-up was 5.3 years and 3.3 years for the CODOX-M/IVAC-R and DA-EPOCH-R group respectively. CODOX-M/IVAC-R demonstrated superior event-free survival (EFS) on univariate (hazard ratio [HR]=0.54, 95% confidence interval [CI]: 0.31-0.97) and multivariable analysis adjusted for age, BCL translocation (BCL2 vs. BCL6 vs. both), International Prognostic Index score and receipt of autologous stem cell transplant (adjusted HR [aHR]=0.52, 95% CI: 0.29-0.93); however there was no significant influence on OS (aHR=0.92, 95% CI: 0.46-1.84). The 1, 2 and 5 years EFS in the CODOX-M/IVAC-R group was 68.3%, 64.1% and 61.5%, respectively compared to 52.4%, 48.9% and 39.5%, respectively in the DA-EPOCH-R group. Primary refractory disease or relapse (R/R) occurred in 33% (16/49) of CODOX-M/IVAC-R and 54% (35/64) of DA-EPOCH-R recipients, and produced median OS of 10.3 months and 33.7 months, respectively, indicating poor outcomes in the CODOX-M/IVAC-R subgroup with R/R disease. More patients were able to receive subsequent salvage therapies in the DA-EPOCH-R group. No patients died of regimen toxicity and the rates of central nervous system relapse and therapy related hematologic neoplasms were similar in both groups.

Double hit lymphoma: contemporary understanding and practices

Double-hit lymphoma (DHL) is a high-risk subtype of large B-cell lymphoma, defined by concurrent rearrangements MYC and BCL2. The diagnosis is confirmed through histologic and immunophenotypic examination and fluorescence in situ hybridization (FISH) to demonstrate the rearrangements. DHL morphology ranges from DLBCL to high-grade B-cell lymphoma which can resemble Burkitt lymphoma and is almost always germinal center B-cell like (GCB). Prognosis is influenced by elevated lactate dehydrogenase (LDH), advanced stage, and extranodal involvement, among other factors. Treatment outcomes vary, but intensive chemotherapy regimens such as dose-adjusted EPOCH-R have shown the most promising results, though low-risk cases do occur and may do well with less intensive treatments. Recent therapeutic advances such as CAR-T cells and bispecific antibodies offer promise for patients with relapsed/refractory disease. This review synthesizes data from recent literature to provide a comprehensive analysis of the molecular underpinnings, diagnostic criteria, prognostic factors, and therapeutic strategies for DHL.

High-grade B-cell lymphoma not otherwise specified, with diffuse large B-cell lymphoma gene expression signatures: Genomic analysis and potential therapeutics

High-grade B-cell lymphoma not otherwise specified (HGBCL, NOS) has overlapping morphological and genetic features with diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma (BL), leading to uncertainty in its diagnosis and clinical management. Using functional genomic approaches, we previously characterized HGBCL and NOS, that demonstrate gene expression profiling (GEP), and genetic signatures similar to BL. Herein, we characterize distinct HGBCL, NOS, cohort (n = 55) in adults (n = 45) and in children (n = 10), and compared the GEP, genomic DNA copy number (CN), and mutational spectrum with de novo DLBCL (n = 85) and BL (n = 52). This subgroup, representing ~60% of HGBCL, NOS, lack gene-expression signature of BL and double hit/dark zone lymphoma, but express DLBCL like signatures and are characterized by either GCB- or ABC-like mRNA signatures and exhibit higher genomic complexity, similar to de novo DLBCL, and show alteration in genes regulating B-cell activation (CD79B, MYD88, PRDM1, TBLIXR1, CARD11), epigenome (KMT2D, TET2) and cell cycle transition (TP53, ASPM). However, recurrent mutations in genes often mutated in BL (DDX3X, GNA13, CCND3), but rare in DLBCL, are also present in HGBCL-NOS, highlighting genetic heterogeneity. Consistent with mutation spectrum, frequent genomic CN alterations in genes regulating B-cell activation (del-PRDM1, gain-BCL6, -REL, -STAT3) and cell cycle regulators (del-TP53, del-CDKN2A, del-RB1, gain-CCND3) were observed. Pediatric cases showed GCB-DLBCL-like mRNA signatures, but also featured hallmark mutations of pediatric BL. Frequent oncogenic PIM1 mutations were present in adult HGBCL, NOS. In vitro analyses with pharmacologic or genetic inhibition of PIM1 expression triggered B-cell activation and NF-κB-induced apoptosis, suggesting that PIM1 is a rational therapeutic target.

A Diagnostic Approach in Large B-Cell Lymphomas According to the Fifth World Health Organization and International Consensus Classifications and a Practical Algorithm in Routine Practice

In this article, we provide a review of large B-cell lymphomas (LBCLs), comparing the recently published fifth edition of the WHO classification and the International Consensus Classification (ICC) on hematolymphoid tumors. We focus on updates in the classification of LBCL, an heterogeneous group of malignancies with varying clinical behaviors and different pathological and molecular features, providing a comparison between the two classifications. Besides the well-recognized diagnostic role of clinical, morphological and immunohistochemical data, both classifications recognize the ever-growing impact of molecular data in the diagnostic work-up of some entities. The main aim is to offer a guide for clinicians and pathologists on how the new classifications can be applied to LBCL diagnosis in routine practice. In the first part of the paper, we review the following categories: LBLs transformed from indolent B-cell lymphomas, diffuse large B-cell lymphoma, not otherwise specified (DLBCL, NOS), double-hit/triple-hit lymphomas (DH/TH), high-grade large B-cell lymphoma, not otherwise specified (HGBCL, NOS), LBCL with IRF4 rearrangement, Burkitt lymphoma (BL) and HGBCL/LBCL with 11q aberration, focusing on the differences between the two classifications. In the second part of the paper, we provide a practical diagnostic algorithm when facing LBCLs in routine daily practice.

Delineating MYC-Mediated Escape Mechanisms from Conventional and T Cell-Redirecting Therapeutic Antibodies

In B-cell malignancies, the overexpression of MYC is associated with poor prognosis, but its mechanism underlying resistance to immunochemotherapy remains less clear. In further investigations of this issue, we show here that the pharmacological inhibition of MYC in various lymphoma and multiple myeloma cell lines, as well as patient-derived primary tumor cells, enhances their susceptibility to NK cell-mediated cytotoxicity induced by conventional antibodies targeting CD20 (rituximab) and CD38 (daratumumab), as well as T cell-mediated cytotoxicity induced by the CD19-targeting bispecific T-cell engager blinatumomab. This was associated with upregulation of the target antigen only for rituximab, suggesting additional escape mechanisms. To investigate these mechanisms, we targeted the MYC gene in OCI-LY18 cells using CRISPR-Cas9 gene-editing technology. CRISPR-Cas9-mediated MYC targeting not only upregulated CD20 but also triggered broader apoptotic pathways, upregulating pro-apoptotic PUMA and downregulating anti-apoptotic proteins BCL-2, XIAP, survivin and MCL-1, thereby rendering tumor cells more prone to apoptosis, a key tumor-lysis mechanism employed by T-cells and NK-cells. Moreover, MYC downregulation boosted T-cell activation and cytokine release in response to blinatumomab, revealing a MYC-mediated T-cell suppression mechanism. In conclusion, MYC overexpressing tumor cells mitigated the efficacy of therapeutic antibodies through several non-overlapping mechanisms. Given the challenges associated with direct MYC inhibition due to toxicity, successful modulation of MYC-mediated immune evasion mechanisms may improve the outcome of immunotherapeutic approaches in B-cell malignancies.

Cytogenetic and pathologic characterization of MYC-rearranged B-cell lymphomas in pediatric and young adult patients

MYC-rearranged B-cell lymphoma (BCL) in the pediatric/young adult (YA) age group differs substantially in disease composition from adult cohorts. However, data regarding the partner genes, concurrent rearrangements, and ultimate diagnoses in these patients is scarce compared to that in adult cohorts. We aimed to characterize the spectrum of MYC-rearranged (MYC-R) mature, aggressive BCL in the pediatric/YA population. A retrospective study of morphologic, immunophenotypic, and fluorescence in situ hybridization (FISH) results of patients age ≤ 30 years with suspected Burkitt lymphoma (BL), diffuse large B-cell lymphoma (DLBCL) or high-grade B-cell lymphoma (HGBCL), and a MYC-R by FISH between 2013-2022 was performed. Two-hundred fifty-eight cases (129 (50%) pediatric (< 18 years) and 129 (50%) YA (18-30 years)) were included. Most MYC-R BCL in pediatric (89%) and YA (66%) cases were BL. While double-hit (DH) cytogenetics (MYC with BCL2 and/or BCL6-R, HGBCL-DH) was rare in the pediatric population (2/129, 2%), HGBCL-DH increased with age and was identified in 17/129 (13%) of YA cases. Most HGBCL-DH had MYC and BCL6-R, while BCL2-R were rare in both groups (3/258, 1%). MYC-R without an IG partner was more common in the YA group (14/116 (12%) vs 2/128 (2%), p = 0.001). The pediatric to YA transition is characterized by decreasing frequency in BL and increasing genetic heterogeneity of MYC-R BCL, with emergence of DH-BCL with MYC and BCL6-R. FISH to evaluate for BCL2 and BCL6 rearrangements is likely not warranted in the pediatric population but should continue to be applied in YA BCL.

Characterization of Human B Cell Hematological Malignancies Using Protein-Based Approaches

The maturation of B cells is a complex, multi-step process. During B cell differentiation, errors can occur, leading to the emergence of aberrant versions of B cells that, finally, constitute a malignant tumor. These B cell malignancies are classified into three main groups: leukemias, myelomas, and lymphomas, the latter being the most heterogeneous type. Since their discovery, multiple biological studies have been performed to characterize these diseases, aiming to define their specific features and determine potential biomarkers for diagnosis, stratification, and prognosis. The rise of advanced -omics approaches has significantly contributed to this end. Notably, proteomics strategies appear as promising tools to comprehensively profile the final molecular effector of these cells. In this narrative review, we first introduce the main B cell malignancies together with the most relevant proteomics approaches. Then, we describe the core studies conducted in the field and their main findings and, finally, we evaluate the advantages and drawbacks of flow cytometry, mass cytometry, and mass spectrometry for the profiling of human B cell disorders.

Distinct peripheral T-cell and NK-cell profiles in HGBL-MYC/BCL2 vs patients with DLBCL NOS

ABSTRACT

Patients with high-grade B-cell lymphoma with MYC and BCL2 rearrangements (HGBL-MYC/BCL2) respond poorly to immunochemotherapy compared with patients with diffuse large B-cell lymphoma not otherwise specified (DLBCL NOS) without a MYC rearrangement. This suggests a negative impact of lymphoma-intrinsic MYC on the immune system. To investigate this, we compared circulating T cells and natural killer (NK) cells of patients with HGBL-MYC/BCL2 (n = 66), patients with DLBCL NOS (n = 53), and age-matched healthy donors (HDs; n = 16) by flow cytometry and performed proliferation, cytokine production, and cytotoxicity assays. Compared with HDs, both lymphoma subtypes displayed similar frequencies of CD8+ T cells but decreased CD4+ T cells. Regulatory T-cell (Treg) frequencies were reduced only in patients with DLBCL NOS. Activated (HLA-DR+/CD38+) T cells, PD-1+CD4+ T cells, and PD-1+Tregs were increased in both lymphoma subtypes, but PD-1+CD8+ T cells were increased only in HGBL-MYC/BCL2. Patients with DLBCL NOS, but not patients with HGBL-MYC/BCL2, exhibited higher frequencies of senescent T cells than HDs. Functional assays showed no overt differences between both lymphoma groups and HDs. Deeper analyses revealed that PD-1+ T cells of patients with HGBL-MYC/BCL2 were exhausted with impaired cytokine production and degranulation. Patients with DLBCL NOS, but not patients with HGBL-MYC/BCL2, exhibited higher frequencies of NK cells expressing inhibiting receptor NKG2A. Both lymphoma subtypes exhibited lower TIM-3+- and DNAM-1+-expressing NK cells. Although NK cells of patients with HGBL-MYC/BCL2 showed less degranulation, they were not defective in cytotoxicity. In conclusion, our results demonstrate an increased exhaustion in circulating T cells of patients with HGBL-MYC/BCL2. Nonetheless, the overall intact peripheral T-cell and NK-cell functions in these patients emphasize the importance of investigating potential immune evasion in the microenvironment of MYC-rearranged lymphomas.

The fifth edition of the WHO classification of mature B-cell neoplasms: open questions for research

The fifth edition of the World Health Organization Classification of Haematolymphoid Tumours (WHO-HAEM5) is the product of an evidence-based evolution of the revised fourth edition with wide multidisciplinary consultation. Nonetheless, while every classification incorporates scientific advances and aims to improve upon the prior version, medical knowledge remains incomplete and individual neoplasms may not be easily subclassified in a given scheme. Thus, optimal classification requires ongoing study, and there are certain aspects of some entities and subtypes that require further refinements. In this review, we highlight a selection of these challenging areas to prompt more research investigations. These include (1) a 'placeholder term' of splenic B-cell lymphoma/leukaemia with prominent nucleoli (SBLPN) to accommodate many of the splenic lymphomas previously classified as hairy cell leukaemia variant and B-prolymphocytic leukaemia, a clear new start to define their pathobiology; (2) how best to classify BCL2 rearrangement negative follicular lymphoma including those with BCL6 rearrangement, integrating the emerging new knowledge on various germinal centre B-cell subsets; (3) what is the spectrum of non-IG gene partners of MYC translocation in diffuse large B-cell lymphoma/high-grade B-cell lymphoma and how they impact MYC expression and clinical outcome; how best to investigate this in a routine clinical setting; and (4) how best to define high-grade B-cell lymphoma not otherwise specified and high-grade B-cell lymphoma with 11q aberrations to distinguish them from their mimics and characterise their molecular pathogenetic mechanism. Addressing these questions would provide more robust evidence to better define these entities/subtypes, improve their diagnosis and/or prognostic stratification, leading to better patient care. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Diagnostic and prognostic molecular pathology of lymphoid malignancies

With the explosion in knowledge about the molecular landscape of lymphoid malignancies and the increasing availability of high throughput techniques, molecular diagnostics in hematopathology has moved from isolated marker studies to a more comprehensive approach, integrating results of multiple genes analyzed with a variety of techniques on the DNA and RNA level. Although diagnosis of lymphoma still relies on the careful integration of clinical, morphological, phenotypic, and, if necessary molecular features, and only few entities are defined strictly by genetic features, genetic profiling has contributed profoundly to our current understanding of lymphomas and shaped the two current lymphoma classifications, the International Consensus Classification and the fifth edition of the WHO classification of lymphoid malignancies. In this review, the current state of the art of molecular diagnostics in lymphoproliferations is summarized, including clonality analysis, mutational studies, and gene expression profiling, with a focus on practical applications for diagnosis and prognostication. With consideration for differences in accessibility of high throughput techniques and cost limitations, we tried to distinguish between diagnostically relevant and in part disease-defining molecular features and optional, more extensive genetic profiling, which is usually restricted to clinical studies, patients with relapsed or refractory disease or specific therapeutic decisions. Although molecular diagnostics in lymphomas currently is primarily done for diagnosis and subclassification, prognostic stratification and predictive markers will gain importance in the near future.

Primary Gastric Atypical Burkitt Lymphoma: A Rare Case Report

The abdomen, particularly the ileocecal region, is the most commonly affected disease site in sporadic Burkitt lymphoma (BL). Involvement of the stomach is very rare. Primary gastric atypical Burkitt lymphoma has not been described in the literature, to the best of our knowledge. In this case report, we discuss a patient with atypical Burkitt lymphoma involving the stomach. The immunohistochemical stains showed positive results for CD20, PAX5, BCL6, CD10, and high ki-67. The fluorescence in situ hybridization (FISH) test revealed a positive result for c-MYC gene rearrangement, but there was no evidence of the typical translocation associated with Burkitt lymphoma involving the IgH, kappa, or lambda genes.

Aggressive B-cell non-Hodgkin lymphomas: a report of the lymphoma workshop of the 20th meeting of the European Association for Haematopathology

Aggressive B-cell non-Hodgkin lymphomas are a heterogeneous group of diseases and our concepts are evolving as we learn more about their clinical, pathologic, molecular genetic features. Session IV of the 2020 EAHP Workshop covered aggressive, predominantly high-grade B-cell lymphomas, many that were difficult to classify. In this manuscript, we summarize the features of the submitted cases and highlight differential diagnostic difficulties. We specifically review issues related to high-grade B-cell lymphomas (HGBCLs) with MYC and BCL2 and/or BCL6 rearrangements including TdT expression in these cases, HGBCL, not otherwise specified, large B-cell lymphomas with IRF4 rearrangement, high-grade/large B-cell lymphomas with 11q aberration, Burkitt lymphoma, and pleomorphic mantle cell lymphoma. Since the workshop, the 5th edition of the WHO Classification for Haematolymphoid Tumours (WHO-HAEM5) and International Consensus Classification (ICC) 2022 were published. We endeavor to use the updated terminology.

Induction treatment in high-grade B-cell lymphoma with a concurrent MYC and BCL2 and/or BCL6 rearrangement: a systematic review and meta-analysis

Background and aim

High-grade B cell lymphomas with concomitant MYC and BCL2 and/or BCL6 rearrangements (HGBCL-DH/TH) have a poor prognosis when treated with the standard R-CHOP-like chemoimmunotherapy protocol. Whether this can be improved using intensified regimens is still under debate. However, due to the rarity of HGBCL-DH/TH there are no prospective, randomized controlled trials (RCT) available. Thus, with this systematic review and meta-analysis we attempted to compare survival in HGBCL-DH/TH patients receiving intensified vs. R-CHOP(-like) regimens.

Methods

The PubMed and Web of Science databases were searched for original studies reporting on first-line treatment in HGBCL-DH/TH patients from 08/2014 until 04/2022. Studies with only localized stage disease, ≤10 patients, single-arm, non-full peer-reviewed publications, and preclinical studies were excluded. The quality of literature and the risk of bias was assessed using the Methodological Index for Non-Randomized Studies (MINORS) and National Heart, Lung, and Blood Institute (NHLBI) Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Random-effect models were used to compare R-CHOP-(like) and intensified regimens regarding 2-year overall survival (2y-OS) and 2-year progression-free survival (2y-PFS).

Results

Altogether, 11 retrospective studies, but no RCT, with 891 patients were included. Only four studies were of good quality based on aforementioned criteria. Intensified treatment could improve 2y-OS (hazard ratio [HR]=0.78 [95% confidence interval [CI] 0.63-0.96]; p=0.02) as well as 2y-PFS (HR=0.66 [95% CI 0.44-0.99]; p=0.045).

Conclusions

This meta-analysis indicates that intensified regimens could possibly improve 2y-OS and 2y-PFS in HGBCL-DH/TH patients. However, the significance of these results is mainly limited by data quality, data robustness, and its retrospective nature. There is still a need for innovative controlled clinical trials in this difficult to treat patient population.

Systematic review registration

https://www.crd.york.ac.uk/prospero, identifier CRD42022313234.

A non-randomized risk-adjusted comparison of lenalidomide + R-CHOP versus R-CHOP for MYC-rearranged DLBCL patients

Patients with MYC rearranged (MYC-R) diffuse large B-cell lymphoma (DLBCL) have a poor prognosis. Previously, we demonstrated in a single-arm phase II trial (HOVON-130) that addition of lenalidomide to R-CHOP (R2CHOP) is well-tolerated and yields similar complete metabolic remission rates as more intensive chemotherapy regimens in literature. In parallel with this single-arm interventional trial, a prospective observational screening cohort (HOVON-900) was open in which we identified all newly diagnosed MYC-R DLBCL patients in the Netherlands. Eligible patients from the observational cohort that were not included in the interventional trial served as control group in the present risk-adjusted comparison. R2CHOP treated patients from the interventional trial (n = 77) were younger than patients in the R-CHOP control cohort (n = 56) (median age 63 versus 70 years, p = 0.018) and they were more likely to have a lower WHO performance score (p = 0.013). We adjusted for differences at baseline using 1:1 matching, multivariable analysis, and weighting using the propensity score to reduce treatment-selection bias. These analyses consistently showed improved outcome after R2CHOP with HRs of 0.53, 0.51, and 0.59, respectively, for OS, and 0.53, 0.59, and 0.60 for PFS. Thus, this non-randomized risk-adjusted comparison supports R2CHOP as an additional treatment option for MYC-R DLBCL patients.

Progression of follicular lymphoma and related entities: Report from the 2021 SH/EAHP Workshop

OBJECTIVES

The 2021 Society for Hematopathology and European Association for Haematopathology Workshop addressed the molecular and cytogenetic underpinnings of transformation and transdifferentiation in lymphoid neoplasms.

METHODS

Session 4, "Transformations of Follicular Lymphoma," and session 5, "Transformations of Other B-Cell Lymphomas," included 45 cases. Gene alteration analysis and expression profiling were performed on cases with submitted formalin-fixed, paraffin embedded tissue.

RESULTS

The findings from session 4 suggest that "diffuse large B-cell lymphoma/high-grade B-cell lymphoma with rearrangements of MYC and BCL2" is a distinct category arising from the constraints of a preexisting BCL2 translocation. TdT expression in aggressive B-cell lymphomas is associated with MYC rearrangements, immunophenotypic immaturity, and a dismal prognosis but must be differentiated from lymphoblastic -lymphoma. Cases in session 5 illustrated unusual morphologic and immunophenotypic patterns of transformation. Additionally, the findings support the role of cytogenetic abnormalities-specifically, MYC and NOTCH1 rearrangements-as well as single gene alterations, including TP53, in transformation.

CONCLUSIONS

Together, these unique cases and their accompanying molecular and cytogenetic data suggest potential mechanisms for and unusual patterns of transformation in B-cell lymphomas and indicate numerous opportunities for further study.

Clinicopathological characteristics associated with the engraftment of patient lymphoma cells in NOG mice

Patient-derived xenograft (PDX) mouse models are useful for deepening our understanding of the biology of malignant lymphoma; however, factors associated with the success of the PDX lymphoma model are largely unknown. We retrospectively analyzed the characteristics of 66 xenotransplantations from 65 patients. In all, 43 (65%) specimens were obtained from patients aged > 60 years, and 42 (64%) specimens were obtained at diagnosis. Specimens were obtained from patients with the following diseases: diffuse large B-cell lymphoma (n = 30), intravascular large B-cell lymphoma (n = 12), follicular lymphoma (n = 8), peripheral T-cell lymphoma (n = 7), mantle cell lymphoma (n = 2), and other (n = 7). The specimens were sourced mainly from bone marrow (n = 31, 47%) and extranodal tumors (n = 13, 20%). Engraftment was successful in 33/66 (50%) xenotransplantations. The median age of patients who provided successful specimens was significantly higher than that for unsuccessful specimens (p = 0.013). Specimens with a high proportion of tumor cells in the graft and those obtained from patients with relapsed/refractory disease showed higher tendencies toward successful engraftment. Taken together, these data suggest that tumor cells with a highly malignant potential might have a high likelihood of engraftment.

Large B-Cell Lymphomas in the 5th Edition of the WHO-Classification of Haematolymphoid Neoplasms-Updated Classification and New Concepts

The family/class of the large B-cell lymphomas (LBCL) in the 5th edition of the World Health Organization (WHO) classification of haematolymphoid tumors (WHO-HAEM5) features only a few major changes as compared to the 4th edition. In most entities, there are only subtle changes, many of them only representing some minor modifications in diagnostic terms. Major changes have been made in the diffuse large B-cell lymphomas (DLBCL)/high-grade B-cell lymphomas (HGBL) associated with MYC and BCL2 and/or BCL6 rearrangements. This category now consists of MYC and BCL2 rearranged cases exclusively, while the MYC/BCL6 double hit lymphomas now constitute genetic subtypes of DLBCL, not otherwise specified (NOS) or of HGBL, NOS. Other major changes are the conceptual merger of lymphomas arising in immune-privileged sites and the description of LBCL arising in the setting of immune dysregulation/deficiency. In addition, novel findings concerning underlying biological mechanisms in the pathogenesis of the different entities are provided.

Clinical impact of 5'MYC or 3'MYC gain/loss detected by FISH in patients with aggressive B-cell lymphomas

FISH analysis using MYC break-apart probes is a widely used technique to assess for MYC rearrangement (MYC-R). Occasionally, FISH results in atypical signal patterns, such as gain or loss of 5^'MYC or 3^'MYC. The clinical impact and/or relationship of these atypical signal patterns to MYC-R are unknown. In this study, we assessed 35 patients who had aggressive B-cell lymphomas and exhibited atypical FISH signal patterns: 3^'MYC deletion (n = 16) or 3^'MYC deletion plus 5^'MYC amplification (n = 5), 5^'MYC gain (n = 10), 5^'MYC deletion (n = 3), and 3^'MYC gain (n = 1). For comparison, we also included 9 patients who showed an unbalanced MYC-R. Patients with 5^'MYC gain showed MYC expression and were often refractory to chemotherapy (n = 7) or had early relapse (n = 2). By contrast, lymphomas with 3^'MYC deletion were negative or had low expression of MYC (16 of 18), and patients often responded to chemotherapy (16 of 19). The median event-free survival was 24, 6, and 4 months for patients with 3^'MYC deletion, 5^'MYC gain and unbalanced MYC-R, respectively (p = 0.0048). We conclude that 5^'MYC gain is associated with MYC expression and a poorer prognosis and likely represents an unbalanced MYC-R. By contrast, 3^'MYC deletions are not associated with MYC expression or a poorer prognosis and this finding may be unrelated to MYC-R.

Classification of B-Cell Lymphomas and Immunodeficiency-Related Lymphoproliferations: What’s New?

New insights from genomic studies have had an impact on the definition and the diagnosis of several lymphoid tumors including follicular B-cell lymphomas, aggressive diffuse large B-cell lymphomas, and lymphoproliferations associated with acquired and posttransplant immunodeficiencies. Follicular lymphoma (FL) includes tumors whose behavior varies widely from indolent/early lesions to aggressive/transformed lymphomas. Although some large B-cell lymphomas can be subclassified as specific entities, the majority lack the characteristics necessary for subclassification and, thus, are termed diffuse large B-cell lymphoma, NOS. There have been, however, some changes in the classification of specific subtypes of large B-cell lymphoma as well as the addition of new entities, a few of which are highlighted in this article. The immunodeficiency-related lymphoproliferative disorders are currently divided into four major categories based on the clinical setting in which they arose: primary immune deficiency, post-transplant, HIV infection, and iatrogenic immunosuppression. In the two upcoming classifications systems for hematolymphoid neoplasms, International Consensus Classification (ICC) and WHO-HAEM-5, there is a divergence in the approach to categorize these lesions. Furthermore, whereas the WHO-HAEM-5 confirms the ability to classify a spectrum of EBV+ lesions as EBV+ DLBCL, NOS, the ICC has separated out lesions that are composed of a heterogenous cellular infiltrate into a new separate category, “EBV-positive polymorphic B cell lymphoproliferative disorder, NOS”. Both WHO-HAEM-5 and ICC recognize a number of KSHV/HHV8-associated lymphoid lesions and acknowledge that there is significant overlap among the different lesions. In the future, translation of these innovations in general practice requires further validation.

Diagnostic approaches and future directions in Burkitt lymphoma and high-grade B-cell lymphoma

Since the 2016 WHO update, progress has been made in understanding the biology of Burkitt lymphoma (BL) and the concept of high-grade B-cell lymphomas (HGBCL) that allows some degree of refinement. The summary presented here reviews in detail the discussions of the Clinical Advisory Committee and expands upon the newly published 2022 International Consensus Classification for lymphoid malignancies (Campo et al. Blood, 2022). BL remains the prototypic HGBCL and diagnostic criteria are largely unchanged. HGBCL with MYC and BCL2 and HGBCL with MYC and BCL6 rearrangements are now separated to reflect biologic and pathologic differences. HGBCL, NOS remains a diagnosis of exclusion that should be used only in rare cases. FISH strategies for diffuse large B-cell lymphoma (DLBCL) and HGBCL are discussed in detail for these diseases. Advances in integrative analysis of mutations, structural abnormalities, copy number, and gene expression signatures allow a more nuanced view of the heterogeneity of DLBCL, NOS as well as definitions of HGBCL and point to where the future may be headed for classification of these diseases.

Copy Number Alteration and Mutational Profile of High-Grade B-Cell Lymphoma with MYC and BCL2 and/or BCL6 Rearrangements, Diffuse Large B-Cell Lymphoma with MYC-Rearrangement, and Diffuse Large B-Cell Lymphoma with MYC-Cluster Amplification

Diffuse large B-cell lymphoma (DLBCL) with MYC alteration is classified as high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements (double/triple-hit lymphoma; DHL/THL), DLBCL with MYC rearrangement (single-hit lymphoma; SHL) and DLBCL with MYC-cluster amplification (MCAD). To elucidate the genetic features of DHL/THL, SHL, and MCAD, 23 lymphoma cases from Tokai University Hospital were analyzed. The series included 10 cases of DHL/THL, 10 cases of SHL and 3 cases of MCAD. The analysis used whole-genome copy number microarray analysis (OncoScan) and a custom-made next-generation sequencing (NGS) panel of 115 genes associated with aggressive B-cell lymphomas. The copy number alteration (CNA) profiles were similar between DHL/THL and SHL. MCAD had fewer CNAs than those of DHL/THL and SHL, except for +8q24. The NGS profile characterized DHL/THL with a higher "mutation burden" than SHL (17 vs. 10, p = 0.010), and the most relevant genes for DHL/THL were BCL2 and SOCS1, and for SHL was DTX1. MCAD was characterized by mutations of DDX3X, TCF3, HLA-A, and TP53, whereas MYC was unmutated. In conclusion, DHL/THL, SHL, and MCAD have different profiles.

The International Consensus Classification of Mature Lymphoid Neoplasms: a report from the Clinical Advisory Committee

Since the publication of the Revised European-American Classification of Lymphoid Neoplasms in 1994, subsequent updates of the classification of lymphoid neoplasms have been generated through iterative international efforts to achieve broad consensus among hematopathologists, geneticists, molecular scientists, and clinicians. Significant progress has recently been made in the characterization of malignancies of the immune system, with many new insights provided by genomic studies. They have led to this proposal. We have followed the same process that was successfully used for the third and fourth editions of the World Health Organization Classification of Hematologic Neoplasms. The definition, recommended studies, and criteria for the diagnosis of many entities have been extensively refined. Some categories considered provisional have now been upgraded to definite entities. Terminology for some diseases has been revised to adapt nomenclature to the current knowledge of their biology, but these modifications have been restricted to well-justified situations. Major findings from recent genomic studies have impacted the conceptual framework and diagnostic criteria for many disease entities. These changes will have an impact on optimal clinical management. The conclusions of this work are summarized in this report as the proposed International Consensus Classification of mature lymphoid, histiocytic, and dendritic cell tumors.

An artificial intelligence system applied to recurrent cytogenetic aberrations and genetic progression scores predicts MYC rearrangements in large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL), the most common type of non-Hodgkin lymphoma, is characterized by MYC rearrangements (MYC R) in up to 15% of cases, and these have unfavorable prognosis. Due to cryptic rearrangements and variations in MYC breakpoints, MYC R may be undetectable by conventional methods in up to 10%-15% of cases. In this study, a retrospective proof of concept study, we sought to identify recurrent cytogenetic aberrations (RCAs), generate genetic progression scores (GP) from RCAs and apply these to an artificial intelligence (AI) algorithm to predict MYC status in the karyotypes of published cases. The developed AI algorithm is validated for its performance on our institutional cases. In addition, cytogenetic evolution pattern and clinical impact of RCAs was performed. Chromosome losses were associated with MYC-, while partial gain of chromosome 1 was significant in MYC R tumors. MYC R was the sole driver alteration in MYC-rearranged tumors, and evolution patterns revealed RCAs associated with gene expression signatures. A higher GPS value was associated with MYC R tumors. A subsequent AI algorithm (composed of RCAs + GPS) obtained a sensitivity of 91.4 and specificity of 93.8 at predicting MYC R. Analysis of an additional 59 institutional cases with the AI algorithm showed a sensitivity and specificity of 100% and 87% each with positive predictive value of 92%, and a negative predictive value of 100%. Cases with a MYC R showed a shorter survival.

Altered pathways and targeted therapy in double hit lymphoma

High-grade B-cell lymphoma with translocations involving MYC and BCL2 or BCL6, usually referred to as double hit lymphoma (DHL), is an aggressive hematological malignance with distinct genetic features and poor clinical prognosis. Current standard chemoimmunotherapy fails to confer satisfying outcomes and few targeted therapeutics are available for the treatment against DHL. Recently, the delineating of the genetic landscape in tumors has provided insight into both biology and targeted therapies. Therefore, it is essential to understand the altered signaling pathways of DHL to develop treatment strategies with better clinical benefits. Herein, we summarized the genetic alterations in the two DHL subtypes (DHL-BCL2 and DHL-BCL6). We further elucidate their implications on cellular processes, including anti-apoptosis, epigenetic regulations, B-cell receptor signaling, and immune escape. Ongoing and potential therapeutic strategies and targeted drugs steered by these alterations were reviewed accordingly. Based on these findings, we also discuss the therapeutic vulnerabilities that coincide with these genetic changes. We believe that the understanding of the DHL studies will provide insight into this disease and capacitate the finding of more effective treatment strategies.

Development of a novel cell line-derived xenograft model of primary herpesvirus 8-unrelated effusion large B-cell lymphoma and antitumor activity of birabresib in vitro and in vivo

BACKGROUND

Primary human herpesvirus 8 (HHV8)-unrelated effusion large B-cell lymphoma is a clinical disease entity distinct from HHV8-positive primary effusion lymphoma (PEL). However, the lack of experimental HHV8-unrelated effusion large B-cell lymphoma models continues to hinder the pathophysiologic and therapeutic investigations of this disorder.

METHODS

The lymphoma cells were obtained from the pleural effusion of a patient with primary HHV8-unrelated effusion large B-cell lymphoma and cultured in vitro.

RESULTS

We established a novel HHV8-unrelated effusion large B-cell lymphoma cell line, designated Pell-1, carrying a c-MYC rearrangement with features distinct from those of HHV8-positive PEL. Moreover, we developed an HHV8-unrelated effusion large B-cell lymphoma cell line-derived xenograft model. Pell-1 cells induced profuse lymphomatous ascites and subsequently formed intra-abdominal tumors after intraperitoneal implantation into irradiated nonobese diabetic/severe combined immunodeficient mice. Thus, this xenograft mouse model mimicked the clinical phenomena observed in patients and recapitulated the sequential stages of aggressive HHV8-unrelated effusion large B-cell lymphoma. The bromodomain and extraterminal domain (BET) inhibitors JQ1 and birabresib (MK-8628/OTX015) reduced the proliferation of Pell-1 cells in vitro through the induction of cell cycle arrest and apoptosis. The antitumor effect of BET inhibition was also demonstrated in vivo, as birabresib significantly reduced ascites and suppressed tumor progression without apparent adverse effects in the xenografted mice.

CONCLUSION

These preclinical findings suggest the therapeutic potential of targeting c-MYC through BET inhibition in HHV8-unrelated effusion large B-cell lymphoma.

Incorporation of next-generation sequencing in clinical practice using solid and liquid biopsy for patients with non-Hodgkin's lymphoma

Although next-generation sequencing (NGS) data on lymphomas require further validation before being implemented in daily practice, the clinical application of NGS can be considered right around the corner. The aim of our study was to validate an NGS lymphoid panel for tissue and liquid biopsy with the most common types of non-Hodgkin’s lymphoma [follicular lymphoma (FL) and diffuse large B-cell lymphoma (DLBCL)]. In this series, 372 somatic alterations were detected in 93.6% (44/47) of the patients through tissue biopsy. In FL, we identified 93 somatic alterations, with a median of 7.4 mutations per sample. In DLBCL, we detected 279 somatic variants with a median of 8.6 mutations (range 0–35). In 92% (24/26) of the cases, we were able to detect some variant in the circulating tumor DNA. We detected a total of 386 variants; 63.7% were detected in both types of samples, 13.2% were detected only in the circulating tumor DNA, and 23% were detected only in the tissue biopsy. We found a correlation between the number of circulating tumor DNA mutations, advanced stage, and bulky disease. The genetic alterations detected in this panel were consistent with those previously described at diagnosis. The liquid biopsy sample is therefore a complementary tool that can provide new genetic information, even in cases where a solid biopsy cannot be performed or an insufficient sample was obtained. In summary, we describe and analyze in this study the findings and difficulties encountered when incorporating liquid biopsy into clinical practice in non-Hodgkin’s lymphoma at diagnosis.

AID is a poor prognostic marker of high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements

Diffuse large B-cell lymphoma with MYC rearrangement is defined as double/triple-hit lymphoma (DHL/THL) or single-hit lymphoma (SHL) by the inclusion of the BCL2 and BCL6 rearrangements status. DHL/THL is called as "high-grade B-cell lymphoma with MYC and BCL2 and/or BCL6 rearrangements" in the World Health Organization 2017 Classification of Tumors of Hematopoietic and Lymphoid Tissues. To find a prognostic biomarker of DHL/THL, we firstly examined 19 cases (molecular analysis series;10 cases of DHL/THL and 9 cases of SHL) with gene expression profile analysis. The gene expression profile analysis showed that the high expression of AICDA was associated with an adverse prognosis in DHL/THL, but not in SHL. Then, we evaluated immunohistochemical expression of AID, the protein product of AICDA, in 50 cases (molecular analysis series of 19 cases and additional immunohistochemistry series of 31 cases; 12 cases of DHL/THL and 19 cases of SHL) and confirmed that its expression was also associated with an adverse prognosis in DHL/THL. Therefore, AICDA and AID can be a predictor of an adverse clinical outcome in DHL/THL and immunohistochemistry of AID is useful to find DHL/THL-adverse prognosis group.

Mutational Landscape of TdT+ Large B-cell Lymphomas Supports Their Distinction From B-lymphoblastic Neoplasms: A Multiparameter Study of a Rare and Aggressive Entity

In the current World Health Organization classification, terminal deoxynucleotidyl transferase (TdT) expression in a high grade/large cell B-cell lymphoma (LBCL) indicates a B-lymphoblastic lymphoma/leukemia (B-LBL), although TdT expression in what appear to be mature LBCL or following mature B-cell neoplasms is reported. The frequency of TdT+ LBCL, how to best categorize these cases, and their clinicopathologic features, molecular landscape, and relationship to classic B-LBL remain to be better defined. TdT expression was therefore assessed in 258 LBCL and the results correlated with the cytologic, phenotypic, and cytogenetic findings. Targeted mutational analysis, review of prior biopsies, and assessment of clinical associations was performed in the 6 cases with >10% TdT+ cells. All 6 TdT+ LBCL were blastoid-appearing, CD34-, MYC+, BCL2+, and had MYC rearrangements (R) (5/6 with BCL2 and/or BCL6-R). 5/6 had a prior TdT- LBCL and/or follicular lymphoma and all had an aggressive course. Fifteen nonsynonymous variants in 11 genes were seen in the 4/5 tested cases with mutations. TdT+ and TdT- areas in 1 case showed identical mutations. The mutational profiles were more like those reported in germinal center B-cell type-diffuse LBCL rather than B-LBL. Evolution from preceding TdT- lymphomas was nondivergent in 1/3 tested cases and partially divergent in 2. The clinicopathologic and cytogenetic features of these 6 cases were similar to those found in a meta-analysis that included additional cases of TdT+ LBCL or B-LBL following follicular lymphoma. Thus, TdT+, CD34- large B-cell neoplasms with MYC rearrangements and often a "double hit" are rare, frequently a transformational event and aggressive but are distinct from classic B-LBL.

Molecular Update and Evolving Classification of Large B-Cell Lymphoma

Diffuse large B-cell lymphomas (DLBCLs) are aggressive B-cell neoplasms with considerable clinical, biologic, and pathologic diversity. The application of high throughput technologies to the study of lymphomas has yielded abundant molecular data leading to the identification of distinct molecular identities and novel pathogenetic pathways. In light of this new information, newly refined diagnostic criteria have been established in the fourth edition of the World Health Organization (WHO) consensus classification of lymphomas, which was revised in 2016. This article reviews the histopathological and molecular features of the various aggressive B-cell lymphoma subtypes included in the updated classification.

Risk for Significant Kidney Function Decline After Acute Kidney Injury in Adults With Hematologic Malignancy

Introduction

Acute kidney injury (AKI) affects 30% of adults hospitalized with hematologic malignancy. Little is known about the long-term impact on kidney outcomes in this population despite the close relationship between kidney function and malignancy treatment eligibility. The purpose of this population-based cohort study was to determine the effect of AKI on kidney function in the year following a new diagnosis of acute leukemia or lymphoma.

Methods

Participants were adults hospitalized within 3 weeks of malignancy diagnosis. Baseline kidney function was determined and AKI diagnosed using standardized criteria. Cox proportional hazard modeling examined the relationship between AKI and a ≥30% decline in estimated glomerular filtration rate (eGFR) from baseline in the 1 year following hospitalization as the primary endpoint.

Results

AKI occurred in 33% of 1064 participants, with 70% of episodes occurring within 48 hours of hospitalization, and significantly increased risk for a ≥ 30% decline in eGFR (hazard ratio [HR] 2.7, 95% confidence interval [CI] 2.2–3.5) and incident chronic kidney disease (HR 2.2, 95% CI 1.7–2.8). AKI remained a significant predictor of eGFR decline in subgroup and multivariable analyses (adjusted HR 1.9, 95% CI 1.4–2.7). A ≥ 30% decline in eGFR increased the risk for death within 1 year in participants with AKI (HR 2.1, 95% CI 1.3–3.3).

Conclusion

Results aid in identifying individuals at highest risk for poor outcomes and highlight the need for research involving interventions that preserve kidney function from the time of initial hospitalization with a hematologic malignancy into the postdischarge period.

High-grade B-Cell Lymphoma With MYC, BCL2, and/or BCL6 Translocations/Rearrangements: Clinicopathologic Features of 51 Cases in a Single Institution of South China

Double-hit/triple-hit lymphomas (DH/THLs) are high-grade B-cell lymphomas with MYC and BCL2 rearrangements and/or BCL6 rearrangements, which have poor outcomes after standard chemoimmunotherapy. This retrospective study analyzed 51 patients (range, 19 to 82 y) diagnosed from 2016 to 2019 and treated for DH/THL (n=34 MYC/BCL6 DHL, n=14 MYC/BCL2 DHL, n=3 THL) at one institution in South China. Extranodal lesions occurred in 32 patients (62.7%), more frequently in MYC/BCL6 DHL (22/34, 64.7%) than in MYC/BCL2 DHL (7/14, 50%). The most common extranodal sites were the stomach (8/32, 25.0%) and intestine (5/32, 15.6%). Most patients (33/45, 73.3%) presented with Ann Arbor stage III/IV. Interestingly, 14.3% (4/28) of MYC/BCL6 DHL tumors showed diffuse, medium-intensity CD30 expression. Epstein-Barr virus-encoded RNA was positive in 3 cases, all MYC/BCL6 DHL. Among 48 patients (94.1%) with follow-up data, 18 (37.5%) died owing to the disease, and the median survival was 5.5 months. Germinal center B cells were observed more frequently in MYC/BCL2 DHL (14/14, 100.0%) than in MYC/BCL6 DHL (15/34, 44.1%; P<0.001). Bone marrow involvement tended to lower overall survival (OS) (P=0.033). No association was observed between stage, B symptoms, lactate dehydrogenase levels, and central nervous system involvement and OS. A total of 25 patients (25/47, 53.2%) with previous hepatitis B virus (HBV) infections had significantly poorer OS (P=0.014). Chronic HBV infection was positively correlated with MYC/BCL6 DHL (r=0.317, P=0.030). Compared with DH/THL in western countries, the disease in South China has distinct characteristics with a higher prevalence of MYC/BCL6 DHL. We speculate that HBV is important in DH/THL tumorigenesis. These findings might provide clues for novel treatment strategies.

ADCs, BiTEs, CARs, and Small Molecules: A New Era of Targeted Therapy in Non-Hodgkin Lymphoma

Novel immunotherapies and small molecular inhibitors are transforming our approach to previously treated and newly diagnosed patients across the spectrum of non-Hodgkin lymphomas (NHLs). Anti-CD19 CAR T cells are now indicated for the treatment of relapsed/refractory aggressive B-cell lymphomas after at least two previous lines of therapy in which durable remissions are achieved in approximately 40% of previously incurable patients. Second-line chemoimmunotherapy remains the standard of care at first relapse, but poor outcomes with conventional treatment in this setting creates an appealing rationale for earlier use of CAR T cells, which is currently under investigation, along with even earlier use in selected high-risk patients in the frontline setting. Other emerging immunotherapies include antibody-drug conjugates (ADCs), such as polatuzumab vedotin for multiple-relapsed diffuse large B-cell lymphoma (DLBCL) in combination with bendamustine-rituximab. Multiple bispecific antibodies that bring malignant B cells in contact with effector T cells appear promising in early clinical trials and will likely emerge as off-the-shelf immunotherapy options. Chemotherapy-free small molecule-based regimens are increasingly available for mantle cell (MCLs) and follicular lymphomas (FLs). Bruton tyrosine kinase inhibitors (BTKi) now represent standard second-line therapy for MCL and are being investigated in combination and as initial therapy. Lenalidomide-rituximab is an active regimen in both FL and MCL and may be used in either relapsed/refractory or previously untreated disease. Three PI3K inhibitors are approved for multiple-relapsed FL and can induce durable remissions in patients with chemotherapy- and rituximab-refractory disease. Additional emerging targeted therapies include BCL2 inhibition in MCL and EZH2 inhibition in FL.

Analysis and impact of a multidisciplinary lymphoma virtual tumor board

The aim is to prospectively evaluate the impact of a multidisciplinary lymphoma virtual tumor board. The utility of multi-site interactive lymphoma-specific tumor boards has not been reported. The Mayo Clinic Lymphoma Tumor Board is a component of the International Mayo Clinic Care Network (MCCN). The format includes the clinical case presentation, presentation of radiology and hematopathology findings by the appropriate subspecialist, proposed treatment options, review of the literature pertinent to the case, pharmacy contributions, and discussion followed by recommendations. Three hundred and nine consecutive highly selected real-time cases with a diagnosis of lymphoma were presented at the Mayo Clinic Lymphoma Tumor Board from January 2014 to June 2018 and decisions were prospectively tracked to assess its impact on the treatment decisions. A total of 309 cases were prospectively evaluated. One hundred and forty (45.3%) cases had some changes made or recommended. The total changes suggested were 179, as some cases had more than one recommendation. There were 93 (30%) clinical management recommendations, 45 (14.6%) additional testing recommendations, 29 (9.4%) pathology changes, and 6 (1.9%) radiology changes. In an electronic evaluation process, 93% of the responders reported an improvement in knowledge and competence, and 100% recommended no change in format of the board. A multidisciplinary lymphoma tumor board approach was found to have a meaningful impact on lymphoma patients while enhancing interdisciplinary interactions and education for multiple levels of the clinical care team.

NCCN Guidelines Insights: B-Cell Lymphomas, Version 3.2019

Diffuse large B-cell lymphomas (DLBCLs) and follicular lymphoma (FL) are the most common subtypes of B-cell non-Hodgkin's lymphomas in adults. Histologic transformation of FL to DLBCL (TFL) occurs in approximately 15% of patients and is generally associated with a poor clinical outcome. Phosphatidylinositol 3-kinase (PI3K) inhibitors have shown promising results in the treatment of relapsed/refractory FL. CAR T-cell therapy (axicabtagene ciloleucel and tisagenlecleucel) has emerged as a novel treatment option for relapsed/refractory DLBCL and TFL. These NCCN Guidelines Insights highlight important updates to the NCCN Guidelines for B-Cell Lymphomas regarding the treatment of TFL and relapsed/refractory FL and DLBCL.

High-Grade B-Cell Lymphomas, Not Otherwise Specified: A Study of 41 Cases

Purpose

To analyze the clinical and pathological characteristics, treatment, and prognosis of high-grade B-cell lymphomas, not otherwise specified (HGBL, NOS), and to increase awareness of this type of lymphoma.

Patients and Methods

We collected clinical and pathological data of 41 cases of newly diagnosed HGBL, NOS, and analyzed diagnosis, prognosis and treatment to examine progression-free survival (PFS) and overall survival (OS).

Results

Among the 41 cases studied, the median PFS was 6.0 months and the median OS was 18.0 months. Compared with patients treated with the R-CHOP regimen, patients treated with a high-intensity chemotherapy (DA-EPOCH-R, R-CODOX-M/IVAC, or R-Hyper-CVAD) had superior PFS and OS (PFS: χ²=4.173, P=0.041; OS: χ²=5.200, P=0.023). A subgroup analysis showed that the OS for the double-expressor lymphoma (DEL) was inferior to that for the non-DEL (χ²=4.563, P=0.033), and this trend was also seen for the single-hit lymphoma with MYC rearrangement (SHL) and the non-SHL (χ²=4.955, P=0.026). Patients with low International Prognostic Index (IPI) scores (≤2) had better survival rates than those with high scores (>2) (PFS: χ²=6.482, P=0.011; OS: χ²=10.156, P=0.001).

Conclusion

HGBL, NOS is associated with a high degree of malignancy, short survival period, and substantial extranodal involvement. High-intensity chemotherapy may improve patient prognosis. While IPI scores statistically correlated with the prognosis, SHL and DEL correlated with an inferior survival rate. New and improved treatments will be needed for HGBL, NOS.

MYD88 mutations identify a molecular subgroup of diffuse large B-cell lymphoma with an unfavorable prognosis

The 2016 World Health Organization classification defines diffuse large B-cell lymphoma (DLBCL) subtypes based on Epstein-Barr virus (EBV) infection and oncogenic rearrangements of MYC/BCL2/BCL6 as drivers of lymphomagenesis. A subset of DLBCL, however, is characterized by activating mutations in MYD88/CD79B We investigated whether MYD88/CD79B mutations could improve the classification and prognostication of DLBCL. In 250 primary DLBCL, MYD88/CD79B mutations were identified by allele-specific polymerase chain reaction or next-generation-sequencing, MYC/BCL2/BCL6 rearrangements were analyzed by fluorescence in situ hybridization, and EBV was studied by EBV-encoded RNA in situ hybridization. Associations of molecular features with clinicopathologic characteristics, outcome, and prognosis according to the International Prognostic Index (IPI) were investigated. MYD88 and CD79B mutations were identified in 29.6% and 12.3%, MYC, BCL2, and BCL6 rearrangements in 10.6%, 13.6%, and 20.3%, and EBV in 11.7% of DLBCL, respectively. Prominent mutual exclusivity between EBV positivity, rearrangements, and MYD88/CD79B mutations established the value of molecular markers for the recognition of biologically distinct DLBCL subtypes. MYD88-mutated DLBCL had a significantly inferior 5-year overall survival than wild-type MYD88 DLBCL (log-rank; P=0.019). DLBCL without any of the studied aberrations had superior overall survival compared to cases carrying ≥1 aberrancy (log-rank; P=0.010). MYD88 mutations retained their adverse prognostic impact upon adjustment for other genetic and clinical variables by multivariable analysis and improved the prognostic performance of the IPI. This study demonstrates the clinical utility of defining MYD88-mutated DLBCL as a distinct molecular subtype with adverse prognosis. Our data call for sequence analysis of MYD88 in routine diagnostics of DLBCL to optimize classification and prognostication, and to guide the development of improved treatment strategies.

High level MYC amplification in B-cell lymphomas: is it a marker of aggressive disease?

While MYC translocations in B-cell lymphoma (BCL) have been extensively studied, the significance of MYC amplification (MYC amp) is poorly understood. This study characterizes BCL showing MYC amp, defined as uncountable FISH signals. Retrospective analysis of all BCL FISH for MYC aberrations performed at our institution (1/2010-2/2018) identified 44/9715 (0.45%) cases with MYC amp. MYC amp probe signals appeared in a cloud-like distribution (70%) or in a single homogenous-staining-region (30%). In total 59% also had MYC separation by breakapart probe indicating concurrent MYC translocation. The most common morphology was large cell (82%) and diagnosis was diffuse large BCL (DLBCL, 50%). In total 88% were germinal center B-cell-like by Hans algorithm. In total 12/42 (29%) cases were "double-hit" by WHO criteria (DHL/THL) in addition to having MYC amp. The estimated 2-year overall survival (OS) of DLBCL cases with MYC amp was 80%. There was no significant difference in OS between DLBCL and DHL/THL among cases with MYC amp, suggesting a poor prognostic impact of MYC amp. However, when compared to a larger cohort of DLBCL and DHL/THL, MYC amp did not have prognostic significance. In summary, MYC amp in BCL is rare, most commonly occurs in DLBCL, and was not associated with survival in our cohort.

Prognostic Significance of MYC Rearrangement and Translocation Partner in Diffuse Large B-Cell Lymphoma: A Study by the Lunenburg Lymphoma Biomarker Consortium

PURPOSE

MYC rearrangement (MYC-R) occurs in approximately 10% of diffuse large B-cell lymphomas (DLBCLs) and has been associated with poor prognosis in many studies. The impact of MYC-R on prognosis may be influenced by the MYC partner gene (immunoglobulin [IG] or a non-IG gene). We evaluated a large cohort of patients through the Lunenburg Lymphoma Biomarker Consortium to validate the prognostic significance of MYC-R (single-, double-, and triple-hit status) in DLBCL within the context of the MYC partner gene.

METHODS

The study cohort included patients with histologically confirmed DLBCL morphology derived from large prospective trials and patient registries in Europe and North America who were uniformly treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone therapy or the like. Fluorescence in situ hybridization for the MYC, BCL2, BCL6, and IG heavy and light chain loci was used, and results were correlated with clinical outcomes.

RESULTS

A total of 5,117 patients were identified of whom 2,383 (47%) had biopsy material available to assess for MYC-R. MYC-R was present in 264 (11%) of 2,383 patients and was associated with a significantly shorter progression-free and overall survival, with a strong time-dependent effect within the first 24 months after diagnosis. The adverse prognostic impact of MYC-R was only evident in patients with a concurrent rearrangement of BCL2 and/or BCL6 and an IG partner (hazard ratio, 2.4; 95% CI, 1.6 to 3.6; P < .001).

CONCLUSION

The negative prognostic impact of MYC-R in DLBCL is largely observed in patients with MYC double hit/triple-hit disease in which MYC is translocated to an IG partner, and this effect is restricted to the first 2 years after diagnosis. Our results suggest that diagnostic strategies should be adopted to identify this high-risk cohort, and risk-adjusted therapeutic approaches should be refined further.

A practical algorithmic approach to mature aggressive B cell lymphoma diagnosis in the double/triple hit era: selecting cases, matching clinical benefit : A position paper from the Italian Group of Haematopathology (G.I.E.)

An accurate diagnosis of clinically distinct subgroups of aggressive mature B cell lymphomas is crucial for the choice of proper treatment. Presently, precise recognition of these disorders relies on the combination of morphological, immunophenotypical, and cytogenetic/molecular features. The diagnostic workup in such situations implies the application of costly and time-consuming analyses, which are not always required, since an intensified treatment option is reasonably reserved to fit patients. The Italian Group of Haematopathology proposes herein a practical algorithm for the diagnosis of aggressive mature B cell lymphomas based on a stepwise approach, aimed to select cases deserving molecular analysis, in order to optimize time and resources still assuring the optimal management for any patient.