B-cell lymphomas with concurrent MYC and BCL2 abnormalities other than translocations behave similarly to MYC/BCL2 double-hit lymphomas

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.

Precision Medicine in Cytopathology

Over the last decade, cancer diagnostics has undergone a notable transformation with increasing complexity. Minimally invasive diagnostic tests, driven by advanced imaging and early detection protocols, are redefining patient care and reducing the need for more invasive procedures. Modern cytopathologists now safeguard patient samples for vital biomarker and molecular testing. In this article, we explore ancillary testing modalities and the role of biomarkers in organ-specific contexts, underscoring the transformative impact of precision medicine. Finally, the advent of more than 80 Food and Drug Administration-approved predictive biomarkers signals a new era, guiding cancer care toward personalized and targeted strategies.

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.

Alternative genetic alterations of MYC, BCL2, and/or BCL6 in high-grade B-cell lymphoma (HGBL) and diffuse large B-cell lymphoma (DLBCL): Can we identify different prognostic subgroups?

High-grade B-cell lymphoma (HGBL)/diffuse large B-cell lymphoma (DLBCL) with rearrangements (R) in MYC and BCL2 and/or BCL6 are correlated with poor prognosis. Little is known about the impact of other genetic alterations (gain (G) or amplification (A)) of these genes. The aim of the study was to investigate whether we can identify new prognostic subgroups. Fluorescence in situ hybridization (FISH) results from 169 HGBL/DLBCL were retrospectively categorized into: (1) concurrent MYC-R and BCL2-R and/or BCL6-R-samples with MYC-R and BCL2-R (+/- BCL6-R); n = 21, and HGBL/DLBCL with MYC-R and BCL6-R; n = 11; (2) concurrent R and G/A in MYC and BCL2 and/or BCL6 called "alternative HGBL/DLBCL"-samples with (n = 16) or without (n = 6) BCL2 involvement; (3) BCL2 and/or BCL6 alterations without MYC involvement (n = 35); (4) concurrent G/A in MYC and BCL2 and/or BCL6 without R (n = 25); and (5) "No alterations" (n = 55). Patients with HGBL/DLBCL-MYC/BCL2 and "alternative" HGBL/DLBCL (with BCL2 involvement) had significantly worse survival rates compared to the "no alterations" group. G/A of these genes in the absence of rearrangements did not show any prognostic significance. HGBL/DLBCL with MYC-R and BCL6-R without BCL2 involvement showed a better survival rate compared to HGBL/DLBCL-MYC/BCL2. According to immunohistochemistry, "double/triple" expression (DEL/TEL) did not show a significantly worse outcome compared to absent DEL/TEL. This study highlights the continued value of FISH assessment of MYC, BCL2, and BCL6 in the initial evaluation of HGBL/DLBCL with different survival rates between several genetic subgroups.

Metastatic Lymphomas of the Placenta: A Literature Review With an Illustrative Case

Lymphoma is the fourth most common tumor to display placental metastasis. This study aimed to report a case of high-grade lymphoma involving the placenta and review the literature on lymphomas metastatic to the placenta. A systematic review was performed following the PRISMA guidelines, using the keywords "lymphoma" AND "placenta." All case reports and case series on lymphoma infiltrating the placenta were collected. Eight cases from 7 studies, including the present case, were synthesized. The mean patient age is 29.5 years. The clinical presentation is non-specific. Hematologic derangements included cytopenias or cytoses, and elevated prothrombin time. The mean gestational age (GA) when a diagnosis of lymphoma was rendered is 27 weeks. Five cases presented with either lymphadenopathy or visceral masses on imaging. Four of these cases eventually led to maternal demise. The mean GA when the fetus was delivered is 31 3/4 weeks. Grossly, most placentas had non-specific findings. Leukemic infiltrates were mostly seen within intervillous spaces. Intravillous infiltrates were associated with high-grade lymphomas, resulting in either maternal demise or stillborn fetuses. This study suggests that the placenta has mechanisms to guard against malignancies; however, these defense mechanisms are not foolproof and may be breached by tumor cells.

Myc rearrangement and concurrent high protein expression of C-Myc/Bcl2 carry an adverse prognosis in diffuse large B-cell lymphoma

PURPOSE

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous group of non-Hodgkin lymphoma, characterized by a variety of clinicopathological, histomorphological, immunophenotypic, and molecular genetic features. The subtype of DLBCL known as double-expressor lymphoma (DEL) is associated with an adverse prognosis when treated with R-CHOP. Our study aimed to investigate the clinicopathologic features of DEL and the prognostic roles of Myc rearrangement and C-Myc expression in DEL patients.

PATIENTS AND METHODS

We conducted a retrospective study of 145 patients who were identified through fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) testing.

RESULTS

We found that DEL patients were more likely to have a non-germinal center B-cell (GCB) subtype, stage III/IV disease, and a high International Prognostic Index (IPI) score. Our survival analysis indicated that Myc rearrangement and C-Myc expression were associated with poor prognosis. Although DEL patients with Myc rearrangement exhibited trends towards worse survival compared with patients without Myc rearrangement, the differences were not statistically significant (P = 0.4008). The median overall survival (OS) of DEL patients with ≥70 % C-Myc expression (DEL-C-Mychigh) was 5 months. In the DEL-C-Mychigh group, the non-GCB subtype showed nonsignificant trends towards poorer survival compared with the GCB subtype (P = 0.1042).

CONCLUSION

In conclusion, our study shows that a cut-off of ≥70 % for C-Myc expression in DEL patients can improve risk stratification, and suggests that more intensive treatment regimens may be necessary to improve survival in this high-risk population.

Lack of reproducibility of histopathological features in MYC-rearranged large B cell lymphoma using digital whole slide images: a study from the Lunenburg lymphoma biomarker consortium

AIMS

Subclassification of large B cell lymphoma (LBCL) is challenging due to the overlap in histopathological, immunophenotypical and genetic data. In particular, the criteria to separate diffuse large B cell lymphoma (DLBCL) and high-grade B cell lymphoma (HGBL) are difficult to apply in practice. The Lunenburg Lymphoma Biomarker Consortium previously reported a cohort of over 5000 LBCL that included fluorescence in-situ hybridisation (FISH) data. This cohort contained 209 cases with MYC rearrangement that were available for a validation study by a panel of eight expert haematopathologists of how various histopathological features are used.

METHODS AND RESULTS

Digital whole slide images of haematoxylin and eosin-stained sections allowed the pathologists to visually score cases independently as well as participate in virtual joint review conferences. Standardised consensus guidelines were formulated for scoring histopathological features and included overall architecture/growth pattern, presence or absence of a starry-sky pattern, cell size, nuclear pleomorphism, nucleolar prominence and a range of cytological characteristics. Despite the use of consensus guidelines, the results show a high degree of discordance among the eight expert pathologists. Approximately 50% of the cases lacked a majority score, and this discordance spanned all six histopathological features. Moreover, none of the histological variables aided in prediction of MYC single versus double/triple-hit or immunoglobulin-partner FISH-based designations or clinical outcome measures.

CONCLUSIONS

Our findings indicate that there are no specific conventional morphological parameters that help to subclassify MYC-rearranged LBCL or select cases for FISH analysis, and that incorporation of FISH data is essential for accurate classification and prognostication.

High-grade B-cell lymphoma (HGBL)-NOS is clinicopathologically and genetically more similar to DLBCL/HGBL-DH than DLBCL

High-grade B-cell lymphoma, not otherwise specified (HGBL-NOS) is rare and data focused on these neoplasms is lacking. We studied the clinicopathologic and genetic features of 136 HGBL-NOS patients and compared them to patients with DLBCL/HGBL-DH (n = 224, defined by 5th Edition WHO) and DLBCL (n = 217). HGBL-NOS patients had clinical features similar to DLBCL/HGBL-DH patients. MYC rearrangement (MYC-R) was present in 43% of HGBL-NOS. With induction regimen similar to DLBCL/HGBL-DH patients, HGBL-NOS patients had a median overall survival (OS) of 28.9 months, similar to DLBCL/HGBL-DH (p = 0.48) but inferior to DLBCL patients (p = 0.03). R-EPOCH induction was associated with improved OS compared with R-CHOP. MYC-R, history of lymphoma, and high IPI were independent adverse prognostic factors in HGBL-NOS patients. Whole transcriptome profiling performed on a subset of HGBL-NOS cases showed a profile more similar to DLBCL/HGBL-DH than to DLBCL; 53% of HGBL-NOS had a DH-like signature (DH-like-Sig) and were enriched for MYC-R. DH-like-Sig+ HGBL-NOS patients had a poorer OS than DH-like-Sig-negative patients (p = 0.04). In conclusion, HGBL-NOS has clinicopathologic features and a gene expression profile more similar to DLBCL/HGBL-DH than to DLBCL. Cases of HGBL-NOS frequently carry MYC-R and have a DH-like-Sig+. R-EPOCH induction in HGBL-NOS appears associated with improved OS compared with standard R-CHOP.

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.

A comparison of the International Consensus and 5th World Health Organization classifications of mature B-cell lymphomas

Several editions of the World Health Organization (WHO) classifications of lympho-hemopoietic neoplasms in 2001, 2008 and 2017 served as the international standard for diagnosis. Since the 4th WHO edition, here referred as WHO-HAEM4, significant clinico-pathological, immunophenotypic and molecular advances have been made in the field of lymphomas, contributing to refining diagnostic criteria of several diseases, to upgrade entities previously defined as provisional and to identify new entities. This process has resulted in two recent classifying proposals of lymphoid neoplasms, the International Consensus Classification (ICC) and the 5th edition of the WHO classification (WHO-HAEM5). In this paper, we review and compare the two classifications in terms of diagnostic criteria and entity definition, with focus on mature B-cell neoplasms. The main aim is to provide a tool to facilitate the work of pathologists, hematologists and researchers involved in the diagnosis and treatment of lymphomas.

Extra copy number of BCL2 is correlated with increased BCL-2 protein expression and poor survival in diffuse large B-cell lymphoma treated with chemoimmunotherapy

The clinical significance of extra copy (EC) genotypes of BCL2, MYC, and BCL6 have not been fully elucidated. We evaluated the EC and translocation statuses of BCL2, MYC, and BCL6 in 190 diffuse large B-cell lymphoma (DLBCL) cases using fluorescence in situ hybridization. EC genotype was sub-classified according to copy number-gained tumor cell ratio (EC1, >20% but ≤50%; EC2, >50%). Only the BCL2-EC groups, not MYC-EC or BCL6-EC groups, displayed significantly increased immunoreactivity of the corresponding protein. Moreover, the BCL2-EC2 group was significantly associated with poor overall survival (OS) and progression-free survival (PFS) in a 147 R-CHOP-treated patient subset, which was also statistically significant as per the multivariate survival analysis for PFS. No significant differences in the survival of MYC, BCL6, concurrent BCL2/MYC, BCL6/MYC, BCL2/BCL6, or triple EC groups were observed. BCL2-EC may contribute to increased BCL-2 protein expression and serve as a predictor of treatment outcomes in DLBCL.

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.

Clinical characteristics and treatment outcomes of children and adolescents with aggressive mature B-cell lymphoma: a single-center analysis

Background

Aggressive mature B-cell non-Hodgkin lymphoma (B-NHL) is the most common non-Hodgkin lymphoma in children. The outcome of chemotherapy for B-NHL has improved over decades.

Methods

We reviewed 82 children and adolescents with B-NHL diagnosed at Asan Medical Center between 1993 and 2020. The D-COMP/COMP (daunomycin–cyclophosphamide, doxorubicin, vincristine, and prednisolone), Pediatric Oncology Group (POG)-9219/9315/9317, R-CHOP/CHOP (rituximab–cyclophosphamide, doxorubicin, vincristine, and prednisolone), and Lymphomes Malins B 89 (LMB89)/LMB96 regimens were administered. In 2018, rituximab was added to the LMB protocol (R-LMB) for advanced-staged Burkitt lymphoma (BL). The patients’ clinical features and treatment outcomes were retrospectively analyzed.

Results

The most common subtype was BL (61%), followed by diffuse large B-cell lymphoma (DLBCL) (35%). The median age was 7.8 (range, 1.3‒16.4) years, and the most frequently used regimen was French‒American‒British (FAB)/LMB96 (58 patients, 70.7%). The 5-year overall survival (OS) and event-free survival (EFS) rates were 92.5% and 85.7%, respectively. The EFS rates of patients with BL and DLBCL were 90.0% and 79.3%, respectively. Among the FAB/LMB risk groups, group C (85.7%) had a significantly lower 5-year OS (P=0.037). Eleven events occurred (6 relapses, 3 deaths, and 2 secondary malignancies) during the median follow-up of 7.1 (range, 3.7‒118.5) months. Two patients treated with R-LMB had good outcomes without complications.

Conclusion

Various treatment regimens have favorable outcomes in pediatric patients with B-NHL. However, further studies are needed to improve survival in high-risk patients. In addition, careful monitoring for acute toxicity or secondary malignancy due to intensive multidrug chemotherapy is required.

Blastoid high-grade B-cell lymphoma initially presenting in bone marrow: a diagnostic challenge

The 2016 WHO classification introduced the category of high-grade B-cell lymphoma (HGBL), which includes one poorly understood subset, blastoid-HGBL. Establishing the diagnosis and distinguishing blastoid-HGBL from B-acute lymphoblastic leukemia (B-ALL) in bone marrow can be challenging. We assessed 31 cases of blastoid-HGBL diagnosed initially in bone marrow and compared this group to 36 cases of B-ALL using immunophenotyping, fluorescence in situ hybridization, and targeted next generation sequencing analysis. The 31 blastoid-HGBL cases included 14 HGBL with MYC and BCL2 and/or BCL6 rearrangements (double hit lymphoma, DHL), 13 HGBL, not otherwise specified (NOS), and four cases with TdT expression that were difficult to classify. Compared with B-ALL, blastoid-HGBL cases more often showed increased intensity/bright expression of CD20, CD38, CD45, BCL-6, and MYC, and less frequent bright expression of CD10 and TdT. Cases of blastoid-HGBL also more frequently had MYC rearrangement, a complex karyotype and TP53 mutation (p < 0.01). With the exception of CD34, no other single factor, including TdT, was sensitive or adequately specific to distinguish blastoid-HGBL from B-ALL. We developed a scoring system using six distinctive features between 16 cases of unequivocal blastoid HGBL and 22 cases of CD34-positive B-ALL, with a score of ≥3 defining blastoid-HGBL. The system was further validated by using 15 cases of surface light chain negative, and/or CD45 dim to negative blastoid-HGBL and 14 cases of CD34-negative B-ALL. The sensitivity, specificity, positive, and negative predictive value of this scoring system were 100%, 94%, 94%, and 100%, respectively. Using this system, the four cases with TdT expression were all classified as blastoid-HGBL: three were DHL and one was HGBL-NOS. In conclusion, blastoid-HGBL shows distinctive immunophenotypic, cytogenetic, and molecular features as compared with B-ALL. The proposed scoring system can be helpful for the classification of diagnostically challenging blastoid lymphoid tumors presenting initially in the bone marrow.

Defining and Treating High-grade B-cell lymphoma, NOS

High-grade B-cell lymphoma, not otherwise specified (HGBL, NOS) is a recently introduced diagnostic category for aggressive B-cell lymphomas. It includes tumors with Burkitt-like or blastoid morphology that do not have double-hit cytogenetics and that cannot be classified as other well-defined lymphoma subtypes. HBCL, NOS are rare and heterogeneous; most have germinal center B-cell phenotype, and up to 45% carry a single-hit MYC rearrangement, but otherwise they have no unifying immunophenotypic or cytogenetic characteristics. Recent analyses utilizing gene expression profiling (GEP) revealed that up to 15% of tumors currently classified as diffuse large B-cell lymphoma display a HGBL-like GEP signature, indicating a potential to significantly expand the HGBL category using more objective molecular criteria. Optimal treatment of HGBL, NOS is poorly defined due to its rarity and inconsistent diagnostic patterns. A minority of patients have early-stage disease which can be managed with standard RCHOP-based approaches with or without radiation. For advanced-stage HGBL, NOS, which often presents with aggressive, disseminated disease, high lactate dehydrogenase, and involvement of extranodal organs (including the central nervous system [CNS]), intensified Burkitt lymphoma-like regimens with CNS prophylaxis may be appropriate. However, many patients diagnosed at age > 60 years are not eligible for intensive immunochemotherapy. An improved, GEP and/or genomic-based pathologic classification that could facilitate HGBL-specific trials is needed to improve outcomes for all patients. In this review, we discuss the current clinicopathologic concept of HGBL, NOS, existing data on its prognosis and treatment, and delineate potential future taxonomy enrichments based on emerging molecular diagnostics.

Fimepinostat (CUDC-907) in patients with relapsed/refractory diffuse large B cell and high-grade B-cell lymphoma: report of a phase 2 trial and exploratory biomarker analyses

Fimepinostat (CUDC-907), a first-in-class oral small-molecule inhibitor of histone deacetylase and phosphatidylinositol 3-kinase, demonstrated efficacy in a phase 1 study of patients with relapsed/refractory (R/R) diffuse large and high-grade B-cell lymphomas (DLBCL/HGBL), particularly those with increased MYC protein expression and/or MYC gene rearrangement/copy number gain (MYC-altered disease). Therefore, a phase 2 study of fimepinostat was conducted in this patient population with 66 eligible patients treated. The primary end-point of overall response (OR) rate for patients with MYC-IHC ≥40% (n = 46) was 15%. Subsequently, exploratory pooled analyses were performed including patients treated on both the phase 1 and 2 studies based upon the presence of MYC-altered disease as well as a biomarker identified by Virtual Inference of Protein activity by Enriched Regulon analysis (VIPER). For these patients with MYC-altered disease (n = 63), the overall response (OR) rate was 22% with seven responding patients remaining on treatment for approximately two years or longer, and VIPER yielded a three-protein biomarker classification with positive and negative predictive values of ≥85%. Prolonged durations of response were achieved by patients with MYC-altered R/R DLBCL/HGBL treated with single-agent fimepinostat. Combination therapies and/or biomarker-based patient selection strategies may lead to higher response rates in future clinical trials.

The Incidence and Treatment Response of Double Expression of MYC and BCL2 in Patients with Diffuse Large B-Cell Lymphoma: A Systematic Review and Meta-Analysis

MYC/BCL2 protein co-expression (i.e., double expressor) has been shown to be a negative predictor of outcome in diffuse large B-cell lymphoma (DLBCL). We aimed to establish the incidence of double expressor status in patients with de novo DLBCL and identify the predictive value of this biomarker on treatment response through systematic review and meta-analysis. PubMed and Embase were searched for studies published through December 2019 that reported proportions of double expressor DLBCL. The pooled proportions of MYC and BCL2 expression, both alone and in combination, were computed using the inverse variance method for calculating weights and by the DerSimonian-Laird method. The pooled odds ratios (ORs) of complete remission (CR) rate were calculated, and meta-regression analysis was conducted to explore heterogeneity. Forty-one studies (7054 patients) were included. The pooled incidence of double expressor status in DLBCL was 23% (95% confidence interval [CI], 20-26%), with an adjusted estimate of 31% (95% CI, 27-36%). Neither MYC/BCL2 protein cutoff values, race, mean, or median age of included patients, or overall study quality was a significant factor of heterogeneity (p ≥ 0.20). Cases without double expressor status demonstrated a higher probability of CR to rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone treatment (OR, 2.69; 95% CI, 1.55-4.67). Our results reaffirm the predictive power of this important biomarker.

Case Report: Concurrent Occurrence of Abdominal Double Expressor Lymphoma and Jejunum Follicular Lymphoma

Double expressor lymphoma (DEL), defined as overexpression of BCL2 and MYC, is an aggressive subtype of diffuse large B cell lymphoma (DLBCL). Here we report a case of a 64-year-old female diagnosed with abdominal DEL transformed from jejunum follicular lymphoma (FL). 18F-fluorodeoxyglucose (FDG)-positron emission tomography showed diffuse accumulation of FDG into the peritoneum and small bowel wall. Double balloon-assisted enteroscopy revealed whitish submucosal tumors in the proximal jejunum. Aggregation of atypical lymphocytes positive for CD20, CD79a, and BCL2 was seen in the jejunal biopsy samples. These atypical lymphocytes were monoclonal since cell surface expression of Ig light chains was limited to κ chain by flow-cytometry. Thus, immunohistochemical and flowcytometric analyses data were consistent with FL of the jejunum. Neoplastic lymphocytes obtained from ascites were positive for CD10, CD20, CD79a, BCL2, and BCL6. Fluorescence in situ hybridization (FISH) showed formation of BCL2/IgH fusion gene and extra copies of MYC, the former of which is a characteristic chromosomal abnormality of FL. These genetic alterations and protein expression profiles of ascitic fluid cells were consistent with those of DEL transformed from FL. Given that a significant population of patients with indolent FL of the gastrointestinal tract developed into aggressive DLBCL, it is likely that primary FL of the jejunum transformed into the abdominal aggressive DEL in this case. This case is unique in that concurrent occurrence of FL and DEL was confirmed by immunohistochemical and FISH analyses and that abdominal DEL transformed from jejunal FL was highly suspected.

Diffuse Large B-Cell Lymphoma: Recognition of Markers for Targeted Therapy

Diffuse large B-cell lymphomas (DLBCL)s, the most common type of Non-Hodgkin’s Lymphoma, constitute a heterogeneous group of disorders including different disease sites, strikingly diverse molecular features and a profound variability in the clinical behavior. Molecular studies and clinical trials have partially revealed the underlying causes for this variability and have made possible the recognition of some molecular variants susceptible of specific therapeutic approaches. The main histogenetic groups include the germinal center, activated B cells, thymic B cells and terminally differentiated B cells, a basic scheme where the large majority of DLBCL cases can be ascribed. The nodal/extranodal origin, specific mutational changes and microenvironment peculiarities provide additional layers of complexity. Here, we summarize the status of the knowledge and make some specific proposals for addressing the future development of targeted therapy for DLBC cases.

Molecular background delineates outcome of double protein expressor diffuse large B-cell lymphoma

Concomitant deregulation of MYC and BCL2 comprises clinically significant, yet poorly characterized biological high-risk feature in diffuse large B-cell lymphoma (DLBCL). To interrogate these lymphomas, we analyzed translocations and protein expression of BCL2, BCL6, and MYC; correlated the findings with comprehensive mutational, transcriptomic, and clinical data in 181 patients with primary DLBCL; and validated the key findings in independent data sets. Structural variations of BCL2 were subtype-specific and specifically increased BCL2 expression. Molecular dissection of MYC deregulation revealed associations with other lymphoma drivers, including loss of TP53, and distinctive gene expression profiles. Double protein expression (DPE) arose from heterogeneous molecular backgrounds that exhibited subtype-dependent patterns. In the germinal center B-cell (GCB) DLBCL, concurrent alterations of MYC and BCL2 loci gave rise to the majority of DPE DLBCLs, whereas among the activated B-cell (ABC) DLBCLs, concurrent alterations were infrequent. Clinically, DPE DLBCL defined a prognostic entity, which was independent of the International Prognostic Index (IPI) and cell of origin, and together with the loss of TP53 had a synergistic dismal impact on survival. In the DPE DLBCL, the loss of TP53 was associated with a chemorefractory disease, whereas among the other DLBCLs, no correlation with survival was seen. Importantly, BCL6 translocations identified non-GCB lymphomas with favorable BN2/C1-like survival independent of IPI and concurrent DPE status. Taken together, our findings define molecular characteristics of the DPE in DLBCL, and recognize clinically feasible predictors of outcome. Given the emerging taxonomical significance of BCL2, BCL6, MYC, and TP53, our findings provide further depth and validation to the genomic classification of DLBCL.

MYC rearrangement but not extra MYC copies is an independent prognostic factor in patients with mantle cell lymphoma

Mantle cell lymphoma (MCL) with MYC rearrangement (MYC-R) is rare and little is known about the importance of MYC extra copies (EC) in the absence of MYC-R in MCL patients. This study includes 88 MCL patients with MYC tested by fluorescence in situ hybridization and/or conventional cytogenetics, including 27 with MYC-R, 21 with MYC-EC, and 40 with normal (NL) MYC. MCL patients with MYC-R more often had blastoid/pleomorphic morphology; a higher frequency of CD10, MYC, and simultaneous MYC and BCL2 expression; a higher level of MYC; and a higher Ki67 proliferation rate (p<0.05) than those without MYC-R. Although patients with MYC-R more frequently received aggressive chemotherapy (p=0.001), their overall survival (OS) was significantly shorter than those without MYC-R. Compared with patients with MYC/BCL2 double hit lymphoma (DHL), patients with MYC-R MCL had a similar OS but more commonly had bone marrow involvement, stage 4 disease, and a different immunophenotype. MCL patients with MYC-EC showed an OS intermediate between those with MYC-R and MYC-NL, either all or only blastoid/pleomorphic MCL patients included. Multivariate analysis showed that MYC-R, but not MYC-EC, had an independent and negative impact on OS. In conclusion, MYC-R but not MYC-EC showed a higher MYC expression and is an adverse prognostic factor for MCL patients. Although the OS of MCL patients with MYC-R is similar to that of MYC/BCL2 DHL patients, these groups have different clinicopathologic features supporting the retention of MCL with MYC-R in the category of MCL, as recommended in the revised World Health Organization classification.

The "Burkitt-like" immunophenotype and genotype is rarely encountered in diffuse large B cell lymphoma and high-grade B cell lymphoma, NOS

Burkitt lymphoma (BL) is a B cell lymphoma composed of monomorphic medium-sized blastic cells with basophilic cytoplasm and a high proliferation index. BL has a characteristic immunophenotype of CD10 and BCL6 positive and BCL2 negative and harbours MYC gene rearrangements (MYCR) in >90% of the cases. Owing to its highly aggressive nature, intensified chemotherapy regimens are usually administered, requiring an exact diagnosis. Since the diagnosis usually warrants an integration of morphologic, immunophenotypic and genetic findings and because there is a morphologic overlap with the new WHO category of high-grade B cell lymphoma, not otherwise specified (HGBL, NOS) and some cases of diffuse large B cell lymphoma (DLBCL), we wanted to test the distinctiveness of the CD10+, BCL6+, BCL2- and MYCR positive immunopheno-genotype in a large cohort of >1000 DLBCL and HGBL. Only 9/982 DLBCL classified by an expert panel of haematopathologists (0.9%) displayed a single MYCR and were CD10+, BCL6+ and BCL2-. In a similar fashion, only one out of 32 HGBL, NOS (3%) displayed the "Burkitt-like" genetic/immunophenotypic constitution. The samples of non-BL showing the BL-typic immunopheno-genotype, interestingly, harboured higher copy number variations (CNV) by OncoScan analysis (mean 7.3 CNVs/sample; range: 2-13 vs. 2.4; range 0-6) and were also distinct from pleomorphic BL cases regarding their mutational spectrum by NGS analysis. This implies that the characteristic immunophenotype of BL, in concert with a single MYCR, is uncommon in these aggressive lymphomas, and that this constellation favours BL.

Integrative genomic analysis focused on cell cycle genes for MYC-driven aggressive mature B-cell lymphoma

MYC is a transcriptional factor that regulates growth and proliferation through cell cycle pathways. MYC alterations, in particular MYC rearrangements, are important in assessing the prognosis of aggressive B-cell lymphoma. In this study, we focused on the impact of nine major cell cycle genes for MYC-driven aggressive mature B-cell lymphoma and analyzed the mutational status using targeted next generation sequencing. Our 40 cases of aggressive mature B-cell lymphomas included 5 Burkitt lymphomas, 17 high-grade B-cell lymphomas and 18 diffuse large B-cell lymphomas with MYC breaks in 100%, 88% and 11%, respectively. Our data allowed a molecular classification into four categories partially independent from the histopathological diagnosis but correlating with the Ki-67 labelling index: (I) harboring TP53 and CDKN2A mutations, being highly proliferative, (II) with MYC rearrangement associated with MYC and/or ID3 mutations, being highly proliferative, (III) with MYC rearrangement combined with additional molecular changes, being highly proliferative, and (IV) with a diverse pattern of molecular alterations, being less proliferative. Taken together, we found that mutations of TP53, CDKN2A, MYC and ID3 are associated with highly proliferative B-cell lymphomas that could profit from novel therapeutic strategies.

Somatic copy number gains in MYC, BCL2, and BCL6 identifies a subset of aggressive alternative-DH/TH DLBCL patients

Double/triple hit lymphoma (DH/TH), known as high-grade B-cell lymphoma (HGBL), is an aggressive diffuse large B cell lymphoma (DLBCL), defined as having concurrent MYC, BCL2, and/or BCL6 gene rearrangements. While gene rearrangements represent significant genetic events in cancer, copy number alterations (CNAs) also play an important role, and their contributions to rearrangements have yet to be fully elucidated. Using FISH and high-resolution CNA data, we defined the landscape of concurrent gene rearrangements and copy gains in MYC, BCL2, and BCL6, in a cohort of 479 newly diagnosed DLBCL. We also show that concurrent translocations and copy number alterations, in combinations similar to DH/TH, identify a unique subset of DLBCL, alternative DH/TH, that have survival outcomes similar to DH/TH DLBCL patients.

Identification of high-risk monomorphic post-transplant lymphoproliferative disorder following solid organ transplantation

Monomorphic post-transplant lymphoproliferative disorder (M-PTLD) occurring after solid organ transplant histologically resembles aggressive non-Hodgkin lymphomas, with diffuse large B-cell lymphoma being the most common. In a cohort of 40 patients with DLBCL-type M-PTLD, inferior progression free survival (PFS) was observed for Revised International Prognostic Index (R-IPI) >2 (p = 0.01) and high-risk pathologic features (p = 0.02), defined by double expressor lymphoma, MYC rearrangement, or increased copy number of either MYC or BCL2. Overall survival (OS) was inferior in R-IPI >2 (p = 0.002) and high-risk pathologic features (p = 0.003). Combining both R-IPI >2 and high-risk pathologic features resulted in well-delineated good, intermediate, and poor risk groups of DLBCL-type M-PTLD with respect to both PFS and OS (p < 0.001). Our results demonstrate a prognostic role for both the R-IPI score and presence of high-risk pathologic features in DLBCL-type M-PTLD.

Clinicopathological and prognostic significance of BCL2, BCL6, MYC, and IRF4 copy number gains and translocations in follicular lymphoma: a study by FISH analysis

BCL2 translocation is the genetic hallmark of follicular lymphoma (FL). Besides BCL2 translocation, copy number (CN) gains and translocations of BCL6, MYC, and IRF4 have also been detected in FL, but there is little information regarding their prognostic significance. This retrospective study used fluorescence in situ hybridization (FISH) to analyze BCL2, BCL6, MYC, and IRF4 translocations and CN gains in 105 FL cases. Genetic translocations were detected for BCL2 (n = 64; 72.7%), BCL6 (n = 14; 15.9%), and MYC (n = 2; 2.3%); no case showed IRF4 translocation. Overall, 23 (26.1%), 30 (34.1%), 12 (13.8%), and 10 (11.0%) cases showed CN gains in BCL2, BCL6, MYC, and IRF4, respectively. BCL6 CN gain was a prognostic factor for worse overall survival, demonstrating a trend toward significance in multivariate analysis (HR =8.769, p = 0.056). BCL6 CN gain in FL might be associated with aggressive biologic behavior.

Patients with double/triple copy number gains on C-MYC, BCL2, and/or BCL6 treated with standard chemotherapy have a similarly poor prognosis than those with high-grade B cell lymphoma with C-MYC and BCL2 and/or BCL6 rearrangements: a single-center experience on a consecutive cohort of large B cell lymphomas

High-grade B cell lymphomas with rearrangements on C-MYC and BCL2 and/or BCL6 (HGBL with MYC and BCL2 and/or Bcl6 rearrangement) are associated with worse clinical outcomes and thus were introduced as a separate new category in the recently updated WHO classification. From 2012 to 2016, we analyzed a consecutive cohort of large B cell lymphomas (LBCLs) for C-MYC, BCL2, and BCL6 rearrangements and correlated our results with clinical-pathological parameters. Ten of 78 (13%) cases had a C-MYC and BCL2 and/or BCL6 rearrangement, so-called double or triple hit (DH), while double/triple copy number gains (CNGs) were found in eight (10%) patients. Patients with a high-grade lymphoma with DH or CNG progressed significantly more often after first-line chemotherapy (p = 0.005). When treated with standard chemotherapy, patients with a DH or CNG had a significantly worse overall (OS) and recurrence free survival (RFS) compared with all other patients (p = 0.033 and p < 0.001, respectively). Thus, patients with a diffuse large B cell lymphoma, harboring a double/triple CNG, seem to have a similar poor prognosis than those with a DH. Though our data can only be regarded as preliminary, our results warrant further investigations to fully elucidate the role of CNGs as well as underlying molecular mechanisms resulting in aggressive behavior in LBCL.

Prognostic impact of diffuse large B-cell lymphoma with extra copies of MYC, BCL2 and/or BCL6: comparison with double/triple hit lymphoma and double expressor lymphoma

Background

The poor outcome of high-grade B-cell lymphoma, with rearrangements of MYC, BCL2 and/or BCL6, also known as double-hit lymphoma or triple-hit lymphoma (DHL or THL), has been well documented, while the clinical significance of extra copies of MYC, BCL2 or BCL6 are still less well known.

Methods

In total, 130 cases of diffuse large B-cell lymphoma, not otherwise specified (DLBCL-NOS) were included in our study. Fluorescence in situ hybridization and immunohistochemistry were performed in all cases to evaluate the genetic status and protein expression levels of MYC, BCL2 and BCL6.

Results

Among the 130 cases of DLBCL, the prevalence rates of extra copies of MYC, BCL2 and BCL6 were 10.8, 20.0 and 14.6%, respectively, and the corresponding rates of gene rearrangement were 10.0, 14.6 and 16.9%, respectively. In total, 7.7% (10/130) of patients were DHL/THL; 9.2% (12/130) of patients were DLBCL with MYC and BCL2 and/or BCL6 gene abnormalities including rearrangements or extra copies, while excluded DHL/THL. The positive protein expression rates of MYC, BCL2 and BCL6 were 46.9% (61), 75.4% (98) and 70.0% (91), respectively. Among the 51 cases with MYC/BCL2 co-expression, 14 cases showed concurrence of MYC, BCL2 and/or BCL6 genetic abnormalities, and the remaining 37 cases were classified as double-expressor lymphoma (DEL). MYC and BCL2 rearrangement and BCL2 extra copies were all associated with upregulated protein expression. Cases with concurrence of MYC, BCL2 and/or BCL6 genetic abnormalities were both associated with MYC/BCL2 co-expression. Patients with concurrence of MYC, BCL2 and/or BCL6 genetic abnormalities excluded DHL/THL had shorter OS (P < 0.001) than patients with DLBCL with no genetic change, and showed no statistical different with patients with DHL/THL (P = 0.419). Extra copies of MYC was independent prognostic factors for DLBCL.

Conclusions

Patients with MYC and BCL2 and/or BCL6 gene extra copies might show a trend towards poor prognosis, and the detection of extra copies of MYC, BCL2 and BCL6 might deserve more attention.

Electronic supplementary material

The online version of this article (10.1186/s13000-019-0856-7) contains supplementary material, which is available to authorized users.

Dissecting diffuse large B-cell lymphomas of the "not otherwise specified" type: the impact of molecular techniques

The updated edition of the Classification of Tumours of Haematopoietic and Lymphoid Tissues, published in September 2017 by the World Health Organization (WHO), presents many important changes to the document published in 2008. Most of these novelties are linked to the exceptional development of biomolecular techniques during the last 10 years. To illustrate how much new technologies have contributed to the better classification of single entities, as well as the discovery of new ones, would go beyond the objectives of this work. For this reason, we will take diffuse large B-cell lymphoma as an example of the cognitive improvement produced by high-yield technologies (such as the gene expression profile, the study of copy number variation, and the definition of the mutational spectrum). The acquisition of this knowledge not only has a speculative value but also represents the elements for effective application in daily practice. On the one hand, it would allow the development of personalised therapy programs, and on the other it would promote the transition from the bench of the researcher's laboratory to the patient's bedside.

Dose-adjusted EPOCH-R (etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab) in untreated aggressive diffuse large B-cell lymphoma with MYC rearrangement: a prospective, multicentre, single-arm phase 2 study

BACKGROUND

MYC gene rearrangement is present in approximately 10% of aggressive B-cell lymphomas, with half also harbouring a BCL2 gene rearrangement. Multiple retrospective studies of R-CHOP (rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone or prednisolone) have shown a worse outcome in patients with MYC rearrangement (alone or with rearrangement of BCL2 or BCL6, or both) than in patients without MYC rearrangement, and suggest improved outcomes after more intensive treatment. We aimed to determine the outcome of dose-adjusted EPOCH-R (etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab; DA-EPOCH-R), an intensive infusional treatment regimen, in untreated aggressive B-cell lymphoma with MYC rearrangement.

METHODS

We present the final analysis of a prospective, multicentre, single-arm, phase 2 study of DA-EPOCH-R in patients with untreated aggressive B-cell lymphoma with MYC rearrangement. DA-EPOCH-R was scheduled to be administered with CNS prophylaxis for six cycles. Primary endpoints included event-free and overall survival. This study is registered with ClinicalTrials.gov (NCT01092182).

FINDINGS

53 patients were enrolled, with median age of 61 years (range 29-80; IQR 50-70); 43 (81%) patients had stage III-IV disease and 26 (49%) had high-intermediate or high international prognostic index (IPI) scores. 19 patients had confirmed MYC rearrangement alone (single-hit) and 24 also had rearrangement of BCL2, BCL6, or both (double-hit), with similar characteristics between these two groups. After a median follow-up of 55·6 months (IQR 50·5-61·1), 48-month event-free survival was 71·0% (95% CI 56·5-81·4) and 48-month overall survival was 76·7% (95% CI 62·6-86·1) for all patients. Toxicity included grade 4 neutropenia in 160 (53%) of 301 cycles, grade 4 thrombocytopenia in 40 (13%) cycles, and any grade of fever with neutropenia in 56 (19%) cycles. There were three treatment-related deaths (all infections).

INTERPRETATION

In this study, DA-EPOCH-R produced durable remission in patients with MYC-rearranged aggressive B-cell lymphomas and should be considered for the treatment of these diseases.

FUNDING

Cancer Trials Support Unit and Center for Cancer Research of the National Cancer Institute and Genentech.

Genomics of aggressive B-cell lymphoma

The growing body of genomic information collected and applied to mature aggressive B-cell lymphoma diagnosis and management has exploded over the last few years due to improved technologies with high-throughput capacity, suitable for use on routine formalin-fixed, paraffin-embedded tissue biopsies, and decreasing costs. These techniques have made evaluation of complete DNA sequences, RNA-expression patterns, translocations, copy-number alterations, loss of heterozygosity, and DNA-methylation patterns possible on a genome-wide level. This chapter will present a case of aggressive B-cell lymphoma and discuss the most important genomic abnormalities that characterize this group of entities in the recent update to the fourth edition of the World Health Organization (WHO) lymphoma classification system. Genomic abnormalities discussed will include those necessary for certain diagnoses such as translocations of MYC, BCL2, or BCL6; gene-expression-profiling categorization; the newly defined Burkitt-like lymphoma with 11q abnormalities; prognostic and predictive mutations, as well as tumor heterogeneity. Finally, our current practices for clinical triage of specimens with a potential diagnosis of aggressive B-cell lymphomas are also described. Options for treatment at relapse, in light of these genomic features, will be discussed in the third presentation from this session.

Radiotherapy for early stage diffuse large B-cell lymphoma with or without double or triple hit genetic alterations

We investigated whether adding radiation (RT) to systemic therapy improved outcomes in early stage diffuse large B-cell lymphoma (DLBCL) patients with or without double- or triple-hit lymphoma (DHL/THL) biology. This analysis included 183 patients profiled with fluorescent in situ hybridization (FISH) for alterations in MYC, BLC2, and/or BCL6. A total of 146 (80%) were non-DHL/THL, 27 (15%) were DHL, and 10 (6%) were THL. Systemic therapy without RT resulted in inferior freedom from relapse (FFR) (HR: 2.28; 95% CI, 1.10-4.77; p = .02). The median FFR for non-DHL/THL was not reached and was 33 and 22.3 months for DHL and THL, respectively; p < .001. Low-risk (R-IPI <2) DHL/THL patients treated with rituximab-based therapy had 3-year FFR rates of 11% and 71% for systemic therapy without and with RT, respectively; p = .04. No differences in overall survival were observed between the treatment groups. Treatment intensification with RT may improve early stage DHL/THL outcomes.

Diagnosis of Lymphoid Lesions in Limited Samples: A Guide for the General Surgical Pathologist, Cytopathologist, and Cytotechnologist

OBJECTIVES

Advances in interventional techniques allow obtaining samples from most body sites through minimally invasive procedures that yield limited samples. We provide practical guidelines for diagnosis of lymphoid lesions in these samples.

METHODS

Guidelines for selection of biopsy site and triage of the specimen according to results of rapid on-site evaluation (ROSE), and description of the advantages and limitations of currently available ancillary studies are described, based on the experience of the authors, complemented by a comprehensive review of the literature.

RESULTS

Five diagnostic categories are observed at ROSE: (1) preponderance of small cells, (2) large cells, (3) mixed small and large cells, (4) blast-like cells, and (5) rare large pleomorphic cells. Detailed description of the diagnostic work-up and subsequent classification for each of these groups is provided.

CONCLUSIONS

A definitive diagnosis of lymphoid neoplasms in limited samples is possible in most cases through correlation of morphology, ancillary studies, and clinical scenario.

MYC, BCL2, and BCL6 rearrangements in primary central nervous system lymphoma of large B cell type

Primary central nervous system lymphoma (PCNSL) is a rare specific subtype of non-Hodgkin lymphoma limited to the brain, leptomeninges, spinal cord, or eyes without any systemic presentation and relapse which mostly takes place in CNS. In more than 95% of patients, it is of diffuse large B cell lymphoma (DLBCL) type. Categorizing PCNSL to germinal center cell like or activated B cell like, as we usually do for DLBCL NOS, may not be applicable for predicting outcome. Possible prognostic significance of MYC, BCL2, and/or BCL6 rearrangements may be important given what we know about their impact in systemic DLBCL, but we have limited knowledge about the status of double or triple hit molecular changes in PCNSL. Here, we have investigated prevalence of these molecular alterations in PCNSL. Two independent tissue microarrays constructed from 78 formalin-fixed paraffin-embedded blocks of confirmed PCNSL were tested for rearrangement of MYC, BCL2, and BCL6 by interphase fluorescent in situ hybridization (FISH) using break apart dual color probes. BCL6 translocation was detected in 15 (12%) cases. Translocation involving MYC and BCL2 was identified in 3 cases (3.8%) and 1 case (1.3%) respectively. One double hit lymphoma was discovered with both MYC/BCL2 translocation (1.3%). To the best of our knowledge, few organized studies have been conducted for MYC, BCL2, and/or BCL6 rearrangement in PCNSL. This study is evaluating large number of PCNSL. Double or triple hit events which are rarely seen in PCNSL.

Advances in pathological understanding of high-grade B cell lymphomas

INTRODUCTION

The designation high-grade B-cell lymphoma (HGBL) has been incorporated into the 2016 Revision of the WHO classification of lymphoid neoplasms and includes two types: (1) HGBL, not otherwise specified; and (2) HGBL with MYC and BCL2 and/or BCL6 rearrangements, also known as double or triple hit lymphoma (DHL/THL). These categories of lymphomas represent 1-2% of non-Hodgkin lymphomas and a considerable portion of DLBCL patients who are primary refractory to R-CHOP therapy. It corresponds to the designation 'B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and Burkitt lymphoma' in the 2008 WHO classification. Areas covered: This paper provides an update of HGBL, focusing on their pathologic features, prognosis, and diagnostic workup. It highlights advances in our understanding of DHL/THL. Expert commentary: The diagnosis relies on FISH testing and the major controversial question is when to perform it to diagnose virtually all DHL/THL cases, but also being cost effective. Currently there is no consensus. Considering the high refractory rate of these patients to standard R-CHOP induction, the authors recommend FISH testing in all newly diagnosed large B-cell lymphoma by using our stepwise test strategy. With the progress of molecular genetics, the prognosis will be further stratified and HGBL-NOS maybe further evolve too.

Prognostic impact of history of follicular lymphoma, induction regimen and stem cell transplant in patients with MYC/BCL2 double hit lymphoma

MYC/BCL2 double hit lymphoma (DHL) has been the subject of many studies; however, no study has systemically compared the clinicopathologic features and prognostic factors between patients with de novo disease versus those with a history of follicular lymphoma (FL). In addition, the prognostic importance of several other issues remains controversial in these patients. In this retrospective study, we assess 157 patients with MYC/BCL2 DHL including 108 patients with de novo disease and 49 patients with a history of FL or rarely other types of low-grade B-cell lymphoma. Patients received induction chemotherapy regimens including 61 R-CHOP, 31 R-EPOCH, 29 R-Hyper-CVAD, and 23 other regimens. Thirty-nine patients received a stem cell transplant (SCT) including 31 autologous and 8 allogeneic. Sixty-two patients achieved complete remission (CR) after induction chemotherapy. Median overall survival (OS) was 19 months. Clinicopathologic features were similar between patients with de novo tumors versus those with a history of FL (P > 0.05). Using multivariate analysis, achieving CR, undergoing SCT, stage and the International Prognostic Index were independent prognostic factors for OS. Stem cell transplantion was associated with improved OS in patients who failed to achieve CR, but not in patients who achieved CR after induction chemotherapy. In conclusion, patients with MYC/BCL2 DHL who present with de novo disease and patients with a history of FL have a similarly poor prognosis. Achievement of CR, regardless of the induction chemotherapy regimen used, is the most important independent prognostic factor. Patients who do not achieve CR after induction chemotherapy may benefit from SCT.

Increased MYC copy number is an independent prognostic factor in patients with diffuse large B-cell lymphoma

Patients with double-hit or triple-hit lymphoma have a significantly worse prognosis compared to patients with diffuse large B-cell lymphoma without MYC rearrangement. However, the prognostic importance of extra copies of MYC, BCL2, or BCL6 has not been fully explored. We studied 663 patients with de novo diffuse large B-cell lymphoma in whom the status of MYC/8q24, BCL2/18q21, and BCL6/3q27 were assessed by fluorescence in situ hybridization. Cases of double or triple extra copy lymphoma were defined by the presence of increased MYC copies and increased BCL2 and/or BCL6 copies or rearrangement. In total, 76 patients with diffuse large B-cell lymphoma had MYC extra copies including 43 cases of double or triple extra copy lymphoma; 105 patients had diffuse large B-cell lymphoma with MYC-R including 56 double- or triple-hit lymphoma; and 482 diffuse large B-cell lymphoma patients had no MYC abnormality (MYC normal). Patients with MYC extra copies, similar to MYC-R, had a worse overall survival compared with MYC normal patients (both P<0.01). The prognosis between patients with MYC extra copies and MYC-R was not statistically significantly different (P=0.086). Cell-of-origin classification failed to correlate with survival in the MYC extra copies group, similar to the MYC-R patient group. Compared with patients with double- or triple-hit lymphoma, patients with double or triple extra copy lymphoma had a higher complete remission rate (P=0.02), but there was no significant statistical difference in overall survival (P=0.089). Intensive induction chemotherapy regimens improved the overall survival of patients with double or triple extra copy lymphoma, but there was no significant improvement of overall survival in patients with MYC-R tumors. Multivariate analysis showed that MYC extra copy in diffuse large B-cell lymphoma is an independent poor prognostic factor, similar to MYC rearrangement.

Diffuse large B-cell lymphoma

Diffuse large B cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma worldwide, representing approximately 30-40% of all cases in different geographic regions. Patients most often present with a rapidly growing tumour mass in single or multiple, nodal or extranodal sites. The most common type of DLBCL, designated as not otherwise specified, represents 80-85% of all cases and is the focus of this review. There are also rare types of lymphoma composed of large B-cells, in aggregate about 15-20% of all neoplasms that are sufficiently distinctive to recognise separately. DLBCL not otherwise specified (referred to henceforth as DLBCL) is a heterogeneous entity in terms of clinical presentation, genetic findings, response to therapy, and prognosis. A major advance was the application of gene expression profiling (GEP) to the study of DLBCL which further clarified this heterogeneity and provided a rationale for subdividing cases into groups. The most popular system divides cases of DLBCL according to cell-of-origin into germinal centre B-cell like (GCB) and activated B-cell like (ABC) subtypes, with about 10-15% of cases being unclassifiable. Patients with the GCB subtype usually have better prognosis than patients with the ABC subtype. Although cell-of-origin is useful for predicting outcome, the GCB and ABC subtypes remain heterogeneous, with better and worse prognostic subsets within each group. Next generation sequencing (NGS) analysis of DLBCL has facilitated global identification of numerous and diverse genetic abnormalities in these neoplasms and has shown that GCB and ABC tumours have different mutation profiles. Although the therapy of patients with DLBCL is an active area of research, the current 5-year overall survival rate is 60-70% using standard-of-care frontline therapy. A precision medicine approach for the design of new therapies based on molecular findings in DLBCL is likely the best path forward. As pathologists, our role has expanded beyond diagnosis. We must perform a complete work-up of DLBCL cases. In addition to our traditional role in establishing the diagnosis, we need to analyse markers that provide information regarding prognosis and potential therapeutic targets. We also must ensure that adequate tissue is triaged for molecular studies which are essential for designing therapy regimens, particularly in the setting of disease relapse.

Diagnosis and classification of hematologic malignancies on the basis of genetics

Genomic analysis has greatly influenced the diagnosis and clinical management of patients affected by diverse forms of hematologic malignancies. Here, we review how genetic alterations define subclasses of patients with acute leukemias, myelodysplastic syndromes (MDS), myeloproliferative neoplasms (MPNs), non-Hodgkin lymphomas, and classical Hodgkin lymphoma. These include new subtypes of acute myeloid leukemia defined by mutations in RUNX1 or BCR-ABL1 translocations as well as a constellation of somatic structural DNA alterations in acute lymphoblastic leukemia. Among patients with MDS, detection of mutations in SF3B1 define a subgroup of patients with the ring sideroblast form of MDS and a favorable prognosis. For patients with MPNs, detection of the BCR-ABL1 fusion delineates chronic myeloid leukemia from classic BCR-ABL1^- MPNs, which are largely defined by mutations in JAK2, CALR, or MPL In the B-cell lymphomas, detection of characteristic rearrangements involving MYC in Burkitt lymphoma, BCL2 in follicular lymphoma, and MYC/BCL2/BCL6 in high-grade B-cell lymphomas are essential for diagnosis. In T-cell lymphomas, anaplastic large-cell lymphoma is defined by mutually exclusive rearrangements of ALK, DUSP22/IRF4, and TP63 Genetic alterations affecting TP53 and the mutational status of the immunoglobulin heavy-chain variable region are important in clinical management of chronic lymphocytic leukemia. Additionally, detection of BRAFV600E mutations is helpful in the diagnosis of classical hairy cell leukemia and a number of histiocytic neoplasms. Numerous additional examples provided here demonstrate how clinical evaluation of genomic alterations have refined classification of myeloid neoplasms and major forms of lymphomas arising from B, T, or natural killer cells.

Genetic profiling of MYC and BCL2 in diffuse large B-cell lymphoma determines cell-of-origin–specific clinical impact

MYC and BCL2 genetic alterations are associated with COO subtype-specific clinical effect in R-CHOP-treated DLBCL.

Primary central nervous system diffuse large B-cell lymphoma shows an activated B-cell-like phenotype with co-expression of C-MYC, BCL-2, and BCL-6

Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma, whose main prognostic factor is closely related to germinal center B-cell-like subtype (GCB- DLBCL) or activated B-cell-like type (non-GCB-DLBCL). The most common type of primary central nervous system lymphoma is diffuse large B-cell type with poor prognosis and the reason is unclear. This study aims to stratify primary central nervous system diffuse large B-cell lymphoma (PCNS-DLBCL) according to the cell-of-origin (COO) and to investigate the multiple proteins expression of C-MYC, BCL-6, BCL-2, TP53, further to elucidate the reason why primary central nervous system diffuse large B-cell lymphoma possesses a poor clinical outcome as well. Nineteen cases of primary central nervous system DLBCL were stratified according to immunostaining algorithms of Hans, Choi and Meyer (Tally) and we investigated the multiple proteins expression of C-MYC, BCL-6, BCL-2, TP53. The Epstein-Barr virus and Borna disease virus infection were also detected. Among nineteen cases, most (15-17 cases) were assigned to the activated B-cell-like subtype, highly expression of C-MYC (15 cases, 78.9%), BCL-2 (10 cases, 52.6%), BCL-6 (15 cases, 78.9%). Unfortunately, two cases were positive for PD-L1 while PD-L2 was not expressed in any case. Two cases infected with BDV but no one infected with EBV. In conclusion, most primary central nervous system DLBCLs show an activated B-cell-like subtype characteristic and have multiple expressions of C-MYC, BCL-2, BCL-6 protein, these features might be significant factor to predict the outcome and guide treatment of PCNS-DLBCLs.