Advances in pathological understanding of high-grade B cell lymphomas

High-grade B-cell lymphomas: Double hit and non-double hit

The classification of high-grade B-cell lymphoma (HGBL) has continuously evolved over past decades. These neoplasms, as currently defined, represent about 2% of all non-Hodgkin lymphomas and patients with these neoplasms are often refractory or relapsed following standard therapy. The 5th edition of the World Health Organization classification of hematologic neoplasms (WHO-HAEM5) has refined the classification of HGBL and recognizes two types: (1) Diffuse large B-cell lymphoma (DLBCL)/HGBL with MYC and BCL2 rearrangements, with or without BCL6 rearrangements; and (2) HGBL, not otherwise specified (HGBL-NOS). WHO-HAEM5 excluded DLBCL/HGBL with concurrent MYC and BCL6 rearrangements from this category and reclassified them into DLBCL or HGBL-NOS categories respectively based on morphology. The International Consensus Classification (ICC) takes a slightly different approach. In addition to recognizing the two WHO-HAEM5 categories, they recognize HGBL with concurrent MYC and BCL6 rearrangements as a provisional entity. In this review, we provide an update of HGBL and its subgroups, focusing on their clinicopathologic features, diagnosis, molecular genetic features, and pathogenesis. Our diagnostic approach and caveats for differential diagnosis are also discussed with an emphasis on the differential diagnosis with B lymphoblastic leukemia/lymphoma.

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.

High-intensity chemotherapy improved the prognosis of patients with high-grade B-cell lymphoma

Objective

High-grade B-cell lymphoma (HGBL) is highly aggressive and has a poor prognosis.

Methods

The clinical data of 76 patients with High-grade B-cell lymphoma treated in our lymphoma center from July 2016 to April 2020 were analyzed retrospectively. The clinical features, treatment and prognosis of patients with two types of high-grade B-cell lymphoma were compared and analyzed.

Results

Among 76 patients with high-grade B-cell lymphoma, 44 cases (57.9%) were high-grade B-cell lymphoma, accompanied by MYC and Bcl-2 and/or Bcl-6 rearrangement (HGBLR) patients, and 32 cases (42.1%) were HGBL, NOS patients. The bone marrow infiltration, IPI (international prognostic index), Ann Arbor stage (III/IV), extranodal disease are more likely to occur in HGBLR group (P <0.05). Survival analysis of patients showed that overall survival (OS) and progression free survival (PFS) in HGBLR group were significantly shorter than those in HGBL, NOS group (median OS: 21 months vs not reached, P=0. 022; median PFS: 5 months vs 12 months, P = 0. 001). Further analysis demonstrated that, as compared with R-CHOP regimen, patients with HGBL who received high-intensity chemotherapy regimens (DA-EPOCH-R, R-CODOX-M/IVAC and R-Hyper-CVAD) had longer OS (median OS, 16 months vs not reached, P=0. 007) and PFS (median PFS, 5 months vs 11 months, P<0.001). Moreover, mu1tivariate ana1ysis showed that high-intensity chemotherapy regimens were independent risk factors for both PFS (P =0.001, HR: 0.306, 95% CI: 0.153-0.610) and OS (P =0.004, HR: 0.262, 95% CI: 0.105-0.656) in patients with HGBL.

Conclusions

HGBLR patients have worse prognosis than patients with HGBL, NOS. High-intensity chemotherapy may improve the prognosis of patients with HGBL.

Double/triple hit lymphoma in the gastrointestinal tract: clinicopathological features, PD-L1 expression and screening strategy

We aimed to detect the clinicopathological features and immune microenvironment of double-hit/triple-hit lymphoma in the gastrointestinal tract (GI-DHL/THL) and identify the best diagnostic strategies. A total of 114 cases, including 15 GI-DHL/THL, 42 non-GI-DHL/THL and 57 control diffuse large B-cell lymphoma (DLBCL) cases, were comparatively analyzed for their clinicopathological characteristics, the expression of the immune-regulatory checkpoint PD-L1 and immune microenvironment. We applied univariate and multivariate analyses to determine predictors of DHL/THL. GI-DHL/THL patients showed a higher prevalence of previous infection with hepatitis B virus (HBV) than those with GI-DLBCL. Morphologically, 87% of cases exhibited features of DLBCL. Regarding immunohistochemistry results, the MYC protein expression and the Ki-67 proliferation index were significantly higher in the GI-DHL/THL group than in the GI-DLBCL group. The main source of PD-L1 expression in DHL was tumor-associated macrophages, whereas some tumor cells were positive for PD-L1 in GI-DLBCL cases, as determined through multiplex immunofluorescence staining. The multivariable logistic analysis suggested that 5 variables, namely, age, Mum1, CD10, MYC, and HBV infection status, reflect the risk of DHL/THL. The GI-DHL/THL group show different clinicopathological features and immune microenvironments from DLBCL, which might suggest that different signaling pathways are involved. More work is needed to elucidate the pathogenic mechanism of GI-DHL/THL.

Machine Learning Models for the Diagnosis and Prognosis Prediction of High-Grade B-Cell Lymphoma

High-grade B-cell lymphoma (HGBL) is a newly introduced category of rare and heterogeneous invasive B-cell lymphoma (BCL), which is diagnosed depending on fluorescence in situ hybridization (FISH), an expensive and laborious analysis. In order to identify HGBL with minimal workup and costs, a total of 187 newly diagnosed BCL patients were enrolled in a cohort study. As a result, the overall survival (OS) and progression-free survival (PFS) of the HGBL group were inferior to those of the non-HGBL group. HGBL (n = 35) was more likely to have a high-grade histomorphology appearance, extranodal involvement, bone marrow involvement, and whole-body maximum standardized uptake (SUVmax). The machine learning classification models indicated that histomorphology appearance, Ann Arbor stage, lactate dehydrogenase (LDH), and International Prognostic Index (IPI) risk group were independent risk factors for diagnosing HGBL. Patients in the high IPI risk group, who are CD10 positive, and who have extranodal involvement, high LDH, high white blood cell (WBC), bone marrow involvement, old age, advanced Ann Arbor stage, and high SUVmax had a higher risk of death within 1 year. In addition, these models prompt the clinical features with which the patients should be recommended to undergo a FISH test. Furthermore, this study supports that first-line treatment with R-CHOP has dismal efficacy in HGBL. A novel induction therapeutic regimen is still urgently needed to ameliorate the poor outcome of HGBL patients.

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.

High-Grade B-Cell Lymphoma (HGBL) with MYC and BCL2 and/or BCL6 Rearrangements Is Predominantly BCL6-Rearranged and BCL6-Expressing in Taiwan

Simple Summary

This study highlights the epidemiological, cytogenetic and clinical difference between patients with multiple hit diffuse large B-cell lymphoma in Taiwan and those from western countries. Unlike in the West, the majority of patients with multiple hit lymphoma in Taiwan harbor a BCL6 rearrangement. Almost three in every five BCL6-rearranged double hit lymphoma cases in Taiwan are non-GCB phenotype, indicating, at least in part, that the preferential screening for double hit with BCL6 rearrangement may be a clinically-informative modality for patients with non-GCB phenotype DLBCL in Taiwan. This also suggests the need for a different treatment approach than is obtained in the West where BCL6 double hit lymphomas are seemingly GCB. Consistent with our present findings, mandatory screening for BCL6-rearrangement in suspected DLBCL cases in Taiwan may aid early diagnosis, therapy decision, and clinical outcome forecast.

Abstract

This study investigated the epidemiological and clinical peculiarities of BCL2 and BCL6 rearrangement in patients with high grade B-cell lymphoma (HGBL) from Taiwan, compared with data from Western countries. Two hundred and eighty-two DLBCL cases from Taipei Medical University-affiliated hospitals (n = 179) and Tri-Service General Hospital (n = 103) were enrolled for this study. From the 282, 47 (16.7%) had MYC translocation; 24 of these harbored concurrent BCL2 and/or BCL6 translocation (double-hit, DH or triple-hit, TH). Twelve DH-HGBL cases had simultaneous MYC and BCL6 translocations, 8 harbored MYC and BCL2 rearrangement, while the remaining 4 patients exhibited TH. Together, 66.7% of DH/TH-HGBL patients were BCL6 rearrangement positive. Among these BCL6-rearranged DH/TH-HGBL patients, only 6 (37.5%) overexpressed MYC and BCL6 proteins simultaneously, indicating that MYC-BCL6 co-overexpression may not be plausible surrogate biomarker for screening BCL6-rearranged DH-HGBL. By the end of year 5, all patients with TH-HGBL, BCL2 DH-HGBL and all but one BCL6 DH-HGBL cases had expired or were lost to follow-up. Progression-free survival (PFS) was longer for the non-DH/TH-HGBL group compared with the DH/TH-HGBL group. While the patients with BCL2 DH-HGBL were lost to follow-up by day 800, their remaining TH-HGBL and BCL6 DH-HGBL peers exhibited very poor PFS, regardless of age strata. More so, patients with BCL6 rearrangement were 5.5-fold more likely associated with extranodal involvement compared with their BCL2-rearranged peers. Moreover, ~60.0% of the BCL6-rearranged DH-HGBL cases were non-GCB, suggesting that including screening for BCL6 rearrangement in patients with the non-GCB phenotype may aid medical decision-making and therapeutic strategy. Contrary to contemporary data from western countries, 2 in every 3 patients with DH/TH-HGBL in Taiwan harbor BCL6 rearrangement. Consistent with present findings, we recommend mandatory screening for BCL6 rearrangement in patients with aggressive HGBL in Taiwan.

Laboratory Workup of Lymphoma in Adults: Guideline From the American Society for Clinical Pathology and the College of American Pathologists

CONTEXT.—

The diagnostic workup of lymphoma continues to evolve rapidly as experience and discovery led to the addition of new clinicopathologic entities and techniques to differentiate them. The optimal clinically effective, efficient, and cost-effective approach to diagnosis that is safe for patients can be elusive, in both community-based and academic practice. Studies suggest that there is variation in practice in both settings.

OBJECTIVE.—

To develop an evidence-based guideline for the preanalytic phase of testing, focusing on specimen requirements for the diagnostic evaluation of lymphoma.

DESIGN.—

The American Society for Clinical Pathology, the College of American Pathologists, and the American Society of Hematology convened a panel of experts in the laboratory workup of lymphoma to develop evidence-based recommendations. The panel conducted a systematic review of literature to address key questions. Using the Grading of Recommendations Assessment, Development, and Evaluation approach, recommendations were derived based on the available evidence, strength of that evidence, and key judgements as defined in the Grading of Recommendations Assessment, Development, and Evaluation Evidence to Decision framework.

RESULTS.—

Thirteen guideline statements were established to optimize specimen selection, ancillary diagnostic testing, and appropriate follow-up for safe and accurate diagnosis of indolent and aggressive lymphoma.

CONCLUSIONS.—

Primary diagnosis and classification of lymphoma can be achieved with a variety of specimens. Application of the recommendations can guide decisions on specimen suitability, diagnostic capabilities, and correct use of ancillary testing. Disease prevalence in patient populations, availability of ancillary testing, and diagnostic goals should be incorporated into algorithms tailored to each practice environment.

Laboratory Workup of Lymphoma in Adults

OBJECTIVES

The diagnostic workup of lymphoma continues to evolve rapidly as experience and discovery lead to the addition of new clinicopathologic entities and techniques to differentiate them. The optimal clinically effective, efficient, and cost-effective approach to diagnosis that is safe for patients can be elusive, in both community-based and academic practice. Studies suggest that there is variation in practice in both settings.

THE AIM OF THIS REVIEW IS TO

develop an evidence-based guideline for the preanalytic phase of testing, focusing on specimen requirements for the diagnostic evaluation of lymphoma.

METHODS

The American Society for Clinical Pathology, the College of American Pathologists, and the American Society of Hematology convened a panel of experts in the laboratory workup of lymphoma to develop evidence-based recommendations. The panel conducted a systematic review of the literature to address key questions. Using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, recommendations were derived based on the available evidence, the strength of that evidence, and key judgments as defined in the GRADE Evidence to Decision framework.

RESULTS

Thirteen guideline statements were established to optimize specimen selection, ancillary diagnostic testing, and appropriate follow-up for safe and accurate diagnosis of indolent and aggressive lymphoma.

CONCLUSIONS

Primary diagnosis and classification of lymphoma can be achieved with a variety of specimens. Application of the recommendations can guide decisions about specimen suitability, diagnostic capabilities, and correct utilization of ancillary testing. Disease prevalence in patient populations, availability of ancillary testing, and diagnostic goals should be incorporated into algorithms tailored to each practice environment.

Oral and oropharyngeal diffuse large B-cell lymphoma and high-grade B-cell lymphoma: A clinicopathologic and prognostic study of 69 cases

OBJECTIVE

The objective of this study was to describe the clinicopathological, molecular, and prognostic features of oral/oropharyngeal diffuse large B-cell lymphoma (DLBCL) and high-grade B-cell lymphoma.

STUDY DESIGN

All cases were retrieved from 7 Brazilian institutions. Immunohistochemical reactions were performed to confirm the diagnoses and to categorize the tumors. In situ hybridization was used to detect Epstein-Barr virus (EBV) and fluorescence in situ hybridization was used to identify gene rearrangements.

RESULTS

Most cases involved the oral cavity (76.8%). Males and females, with a mean age of 60 years, were evenly affected. Tumors mostly presented as painful swellings. Forty cases represented germinal center B-cell type (58%). Five cases presented double-hit translocation and 3 harbored rearrangement for MYC/BCL2/BCL6. EBV was detected in 3 cases (4.3%). The 5-year overall survival was 44.4%. Female sex, presence of pain and ulcer, microscopic "starry sky pattern" and necrosis, co-expression of c-Myc/Bcl2, and translocation of MYC were associated with a lower survival in univariate analysis (P = .05, P = .01, P = .01, P = .03, P = .05, P = .006, P = .05, respectively).

CONCLUSION

Patients affected by oral/oropharyngeal DLBCL have a low survival rate. High-grade B-cell lymphoma (17.7%) and EBV-positive DLBCL, not otherwise specified (4.3%) account for a small number of cases.

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.

MYC rearrangement and MYC/BCL2 double expression but not cell-of-origin predict prognosis in R-CHOP treated diffuse large B-cell lymphoma

OBJECTIVE

Diffuse large B-cell lymphoma (DLBCL) can be classified as germinal center B cell-like (GCB) or activated B cell-like (ABC)/non-GCB based on cell-of-origin (COO) classification. This study evaluated the prognostic significance of COO classification in 250 patients diagnosed with de novo DLBCL who received R-CHOP therapy. We also assessed whether the genomic status of MYC, BCL2, or MYC/BCL2 double expression (DE) could provide additional prognostic information for DLBCL patients.

METHODS

The clinicopathologic features and outcome of patients with GCB DLBCL were compared to patients with non-GCB DLBCL using Fisher's exact test. The prognostic significance of COO, MYC-R, and MYC/BCL2 DE were studied using multivariate Cox proportional hazard analysis.

RESULTS

There were 162 men and 88 women with a median age of 62 years (range, 18-86). Forty-five of 250 (18%) cases harbored MYC rearrangement (R). The frequency of MYC-R was much higher in GCB than in non-GCB tumors (40/165, 24% vs 5/85, 6%) (P = .0001). MYC/BCL2 DE was observed in 53 of 125 (42%) cases. COO classification failed to predict overall survival (OS) in DLBCL patients, either those patients with MYC-R were included (P = .10) or not (P = .27). In contrast, MYC-R and MYC/BCL2 DE significantly correlated with inferior OS (P = .0001 and P = .001, respectively). In multivariate analysis, MYC-R and MYC/BCL2 DE were still independent prognostic factors in DLBCL patients.

CONCLUSIONS

MYC-R and MYC/BCL2 DE are independent prognostic factors for DLBCL patients treated with R-CHOP. In this cohort, COO classification failed to stratify patient outcome.