Double-hit lymphomas: clinical, morphological, immunohistochemical and cytogenetic study in a series of Brazilian patients with high-grade non-Hodgkin lymphoma

Clinicopathologic and genetic features of the starry-sky pattern in double-expressor diffuse large B-cell lymphoma

Double expressor lymphoma (DEL) is a subset of diffuse large B-cell lymphoma (DLBCL) characterized by the co-expression of MYC and BCL2 proteins with a poor prognosis. However, there are no standard criteria for evaluating the morphologic features of DEL. We aimed to analyze the prognostic value of the starry-sky pattern (SSP) and its correlation with clinicopathologic and genetic features in 153 DEL cases. The SSP was significantly associated with aggressive parameters, including c-MYC overexpression, CD5 expression, higher IPI, and age-adjusted IPI. In the univariate survival analyses, the presence of SSP was associated with unfavorable progression-free survival (PFS) (p = 0.040), and tended towards an adverse overall survival (OS) (p = 0.061). However, when c-MYC was overexpressed, SSP was significantly correlated with inferior OS (p = 0.019). In the multivariate survival analysis, SSP was also associated with poor PFS (p = 0.048). Additionally, next-generation sequencing data revealed SSP was significantly associated with the KMT2D mutation and had different genetic mutation profiles from non-SSP. In conclusion, SSP may represent morphologic characteristics of aggressiveness in DEL.

c-MYC and p53 expression highlight starry-sky pattern as a favourable prognostic feature in R-CHOP-treated diffuse large B-cell lymphoma

Diffuse large B-cell lymphoma (DLBCL) is a clinically heterogeneous entity, in which the first-line treatment currently consists of an immuno-chemotherapy regimen (R-CHOP). However, around 30% of patients will not respond or will relapse. Overexpression of c-MYC or p53 is frequently found in DLBCL, but an association with prognosis remains controversial, as for other biomarkers previously linked with DLBCL aggressivity (CD5, CD23, or BCL2). The aim of this study was to explore the expression of these biomarkers and their correlation with outcome, clinical, or pathological features in a DLBCL cohort. Immunohistochemical (c-MYC, p53, BCL2, CD5, and CD23), morphological ('starry-sky' pattern [SSP]), targeted gene panel sequencing by next-generation sequencing (NGS), and fluorescence in situ hybridisation analyses were performed on tissue microarray blocks for a retrospective cohort of 94 R-CHOP-treated de novo DLBCL. In univariate analyses, p53 overexpression (p53^high ) was associated with unfavourable outcome (p = 0.04) and with c-MYC overexpression (p = 0.01), whereas c-MYC overexpression was linked with an SSP (p = 0.004), but only tended towards an inferior prognosis (p = 0.06). Presence of a starry-sky morphology was found to be correlated with better survival in p53^high DLBCL (p = 0.03) and/or c-MYC-positive DLBCL (p = 0.002). Furthermore, NGS data revealed that these three variables were associated with somatic mutations (PIM1, TNFRSF14, FOXO1, and B2M) involved in B-cell proliferation, survival, metabolism, and immune signalling. Taken together, these results show that the SSP pattern seems to be a protective factor in high-risk DLBCL subgroups and highlight cell death as a built-in failsafe mechanism to control tumour growth.

Double Hit and Double Expresser Diffuse Large B Cell Lymphoma Subtypes: Discrete Subtypes and Major Predictors of Overall Survival

Double hit lymphomas (DHL) and double expresser lymphomas (DEL) are subsets of diffuse large B cell lymphomas (DLBCL) which are being increasingly recognised as cause of treatment failure. This emphasizes the need for their separation from other DLBCL cases in order to prognosticate and administer more aggressive treatment to this set of patients. The present study was conducted with the aim to identify the DHL/DEL patients and study their distinctive clinicopathological profile and overall survival. This retrospective analysis involved 172 cases of DLBCL sub-classified on the basis of cell of origin. Immunohistochemical (IHC) analysis for MYC, BCL2, BCL6, MUM1 and CD10 was performed. Rearrangement studies were performed using break apart Fluorescent in situ hybridization. Overall survival (OS) was also evaluated. Distinctive clinical and pathological features of DHL and DEL were identified. Rearrangement study by FISH revealed seven cases of DHL (MYC + BCL2 &/or BCL6 rearrangement). Also, 20 patients (11.6%) showed a concurrent expression of BCL2 and MYC oncoproteins (DEL) on IHC. Most (6/7) DHL patients were double expressors also. The DHL patients demonstrated a significant association with female gender, high serum LDH levels (> 750 U/L) and GCB phenotype. DEL patients contrarily predominated amongst males, had intermediate LDH levels (251-500 U/L) and non GCB phenotype. The OS of the patients was 63.8% at 4 years. The OS of the DLBCL, DEL and DHL patients was 71.9%, 46.9%, and 0%, respectively at 4 years (p value 0.010). In case of DEL subtype, factors such as age < 60 years (66.7%), male sex (60.8%), nodal localization (52.5%), early disease stage (84.6%), low IPI score (60%), absence of B symptoms (50%), LDH < 250 U/L (80%) and GCB phenotype (53.3%) were associated with better OS. Further, the OS of DHL cases was 0% at 4 years. Double hit and double expresser lymphomas have poor prognostic outcomes and should be separated from DLBCL. All DELs should be tested for DHLs and especially those with immunoblastic morphology. DHL and DEL subtypes delineate the subtypes with inferior OS and reinstate the need for aggressive interventions.

50% versus 70%: is there a difference between these BCL2 cut-offs in immunohistochemistry for diffuse large B-cell lymphomas (DLBCL)?

Introduction

The World Health Organization’s (WHO) update of 2017 defines the cut-off for BCL2 in immunohistochemistry (IHC) in 50% of stained cells in diffuse large B-cell lymphomas (DLBCL). The WHO’s 2017 classification, however, has no standardized value. This study analyzes associations between immunohistochemistry results for BCL2 in relation to the detection of translocations of MYC, BCL2, and BCL6 in DLBCL.

Method

Sixty-seven patients with DLBCL were evaluated using IHC, with CD20, CD10, BCL6, BCL2, MUM1, TDT and MYC, and fluorescence in situ hybridization (FISH) for translocations involving the BCL2, BCL6, and MYC. Two cut-offs for BCL2 in IHC were used (50 and 70%), with the calculation of sensitivity (S), specificity (E), positive predictive value (PPV), negative predictive value (NPV), accuracy and concordance test, with a significance level of 5%.

Results

Using a 70% cut-off, there is a good relationship between S (88.9%, IC95% = 68.4–109.4) and E (67.2, 95% CI = 55.2–79.3), with a high NPV (97.5, 95% CI = 92.7–102.3) and statistically significant agreement (K = 0.30, p = 0.02). Using a 50% cut-off, S and NPV increase to 100%, with a specificity of 39.7% (95% CI = 27.1–52.2) and a statistically significant concordance (K = 0.15, p = 0.017).

Conclusion

Reduction in the percentage of immunostaining increases the detection of DLBCL with a “double-expressor” immunophenotype. The lower criterion amplifies the S and the NPV of IHC to detect translocations involving the BCL2 gene, with an impact on the diagnosis of DLBCL “double expressor”, an unfavorable prognostic group.

EZH2 expression is dependent on MYC and TP53 regulation in diffuse large B-cell lymphoma

EZH2 is an important epigenetic regulator, but its role in diffuse large B-cell lymphoma (DLBCL) pathogenesis and its relationship with MYC, BCL2, and TP53 expression, chromosomal rearrangements, and clinical features are still poorly understood. So, we investigated EZH2 expression and its associations with the immunophenotypic presentations, including MYC, BCL2, and TP53 expression, MYC, BCL2, and BCL6 translocation status, clinicopathological features, and therapeutic response to R-CHOP in a series of 139 DLBCL cases. EZH2 positivity was associated with MYC and TP53 expression (p = 0.0002 and p = 0.0000, respectively) and to high proliferative index (Ki67>70%, p = 0.0082). No associations were found among EZH2 expression and chromosomal translocation status. The non-germinal center (nGC) DLBCL presented most of associations observed in the general sample; however, only TP53 immunodetection showed associations with EZH2 expression in the germinal center (GC) DLBCL. EZH2 expression had no impact on therapeutic efficacy in R-CHOP-treated patients. In conclusion, EZH2 seems to be upregulated by MYC, to rely on TP53 alterations, and is associated with high proliferative tumors in DLBCL, which might be dependent on GC or nGC subclassifications. Furthermore, it is not a therapeutic efficacy marker to R-CHOP in our series.

HIV-Associated "Double-Hit" Lymphoma of the Tonsil: A First Reported Case

Double-hit lymphoma (DHL) is a unique subtype of non-Hodgkin lymphoma characterized by atleast two rearrangements involving MYC, BLC2, and/or BCL6. These lymphomas are uncommon and aggressive, responding poorly to typical chemotherapy regimens. Lymphomas rarely arise from the oral cavity or tonsils, and those presenting as a neck mass are predominantly diffuse large B-cell lymphoma. To date, primary DHL of the tonsils has yet to be described in the literature. Here, we report a case of a 44 year-old male patient with well-controlled human immunodeficiency virus (HIV) who presented with a sore throat. He subsequently developed acute respiratory compromise due to a rapidly enlarging tonsillar mass. Pathologic and genetic analysis confirmed the presence of BCL6 and MYC rearrangements suggestive of DHL of the tonsils. In a young patient with HIV and a neck mass, it is essential that lymphoma remains on the list of differential diagnoses as prompt diagnosis and treatment may prevent complications from its rapid expansion.

C-MYC and BCL2: Correlation between Protein Over-Expression and Gene Translocation and Impact on Outcome in Diffuse Large B Cell Lymphoma

Background: Due to lack of availability of gene expression profiling (GEP) for most developing countries and clinicians; the immunohistochemistry (IHC) is mostly used in the clinical application. The aim of our study is to check the possibility of using IHC to detect MYC and BCL2 in our patients with diffuse large B-cell lymphoma (DLBCL) instead of GEP to stratify them into high and low-risk groups. This will help in a proper treatment choice of subsequent improvement in the survival outcome. Method: During the study period, 90 DLBCL patients were eligible. MYC and BCL2 evaluated by IHC and gene rearrangement by real-time PCR (RT-PCR) and correlated with clinical-pathological features and survival. Results: Through IHC, the expression of MYC, BCL2, and double expression was detected in 35.6%, 46.7% and 30% of patients, respectively. While by RT-PCR, it was 4.53±0.74 for MYC compared with 2.18±0.78 for BCL-2. Most patients with BCL2+/MYC+; double-expressor and double-hit lymphomas (DEL and DHL) had high stage (III, IV), more extra-nodal involvement, (P value <0.001) and intermediate to high International Prognostic Index (IPI) risk profile (P-value <0.001). The median overall survival was 14 months and 6 months for DEL and DHL, respectively. While all patients with DHL died during the follow-up period, the median PFS were only 2 months for DEL. There was a statistically significant correlation between mRNA of MYC and BCL2 with their protein expression (p<0.001). Conclusion: Our results confirmed the unique characters and poor outcome associated with DEL and DHL mandated the need for more intense therapy and not the standard protocol. Moreover, the significant correlation between protein overexpression and gene rearrangement may open the door for the possibility to use IHC instead of RT-PCR in developing countries.

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.

Epstein–Barr Virus: A Biological Overview and Clinicopathological Changes of Two Epstein–Barr Virus-Related Lymphoproliferative Disorders in a World Health Organization (WHO) 2017 Report

Epstein–Barr virus (EBV) is one of the most important viral causes for the development of tumours. The global geographical epidemiology of EBV shows prevalence differences between rich and poor countries across the world, and the impact on health suggests EBV should be an important target of research worldwide. This article will discuss the biology of the virus with an emphasis on its latency types, vital to understanding the possibilities of viral detection. The main objective is to discuss two lymphoproliferative diseases that are associated with EBV and appear in the World Health Organization (WHO) 2017 Classification of Tumours of Haematopoietic and Lymphoid Tissues: EBV-positive diffuse large B cell lymphoma and EBV mucocutaneous ulcer. The name of the former was changed to support the better understanding of infection pathology, while the second was recently described and made its debut in the WHO classification. Pathologists must have knowledge on these diseases and how to investigate them, and oncologists and clinical doctors must be informed on the guidelines.