Prognostic Impact of MUM1/IRF4 Expression in Burkitt Lymphoma (BL): A Reappraisal of 88 BL Patients in Japan

Emerging roles for heterogeneous ribonuclear proteins in normal and malignant B cells

Heterogeneous nuclear ribonucleoproteins (hnRNPs) are among the most abundantly expressed RNA binding proteins in the cell and play major roles in all facets of RNA metabolism. hnRNPs are increasingly appreciated as essential for mammalian B cell development by regulating the carefully ordered expression of specific genes. Due to this tight regulation of the hnRNP-RNA network, it is no surprise that a growing number of genes encoding hnRNPs have been causally associated with the onset or progression of many cancers, including B cell neoplasms. Here we discuss our current understanding of hnRNP-driven regulation in normal, perturbed, and malignant B cells, and the most recent and emerging therapeutic innovations aimed at targeting the hnRNP-RNA network in lymphoma.

Genetic and phenotypic characterisation of HIV-associated aggressive B-cell non-Hodgkin lymphomas, which do not occur specifically in this population: diagnostic and prognostic implications

The frequency of aggressive subtypes of B-cell non-Hodgkin lymphoma (B-NHL), such as high-grade B-cell lymphomas (HGBL) with MYC and BCL2 and/or BCL6 rearrangement (HGBL-DH/TH) or Burkitt-like lymphoma (BL) with 11q aberration, is not well known in the HIV setting. We aimed to characterise HIV-associated aggressive B-NHL according to the 2017 WHO criteria, and to identify genotypic and phenotypic features with prognostic impact. Seventy-five HIV-associated aggressive B-NHL were studied by immunohistochemistry (CD10, BCL2, BCL6, MUM1, MYC, and CD30), EBV-encoded RNAs (EBERs), and fluorescence in situ hybridisation (FISH) to evaluate the status of the MYC, BCL2, and BCL6 genes and chromosome 11q. The 2017 WHO classification criteria and the Hans algorithm, for the cell-of-origin classification of diffuse large B-cell lymphomas (DLBCL), were applied. In DLBCL cases, the frequencies of MYC and BCL6 rearrangements (14.9 and 27.7%, respectively) were similar to those described in HIV-negative patients, but BCL2 rearrangements were infrequent (4.3%). MYC expression was identified in 23.4% of DLBCL cases, and coexpression of MYC and BCL2 in 13.0%, which was associated with a worse prognosis. As for BL cases, the expression of MUM1 (30.4%) conferred a worse prognosis. Finally, the prevalence of HGBL-DH/TH and BL-like with 11q aberration are reported in the HIV setting. The phenotypic and genotypic characteristics of HIV-associated aggressive B-NHL are similar to those of the general population, except for the low frequency of BCL2 rearrangements in DLBCL. MYC and BCL2 coexpression in DLBCL, and MUM-1 expression in BL, have a negative prognostic impact on HIV-infected individuals.

Epstein-Barr virus and Burkitt's lymphoma. Associations in Iraqi Kurdistan and twenty-two countries assessed in the International Incidence of Childhood Cancer

Background

Burkitt's lymphoma (BL) has worldwide variations in incidence that are related to the age of Epstein-Barr virus (EBV) infection. This study examined the age-specific incidence rate (ASIR) of BL and community EBV seropositivity in Iraqi Kurdistan and compared results with data from countries tabulated in the International Incidence of Childhood Cancer volume 3 (IICC-3).

Methods

The ASIR (95% confidence intervals) of BL in Sulaimani Governorate of Iraqi Kurdistan were calculated for the years 2010–2020. Specimens from 515 outpatients were tested for IgG and IgM antibodies to EBV viral capsid antigen.

Results

In Sulaimani, 84% of BL occurred under 20 years of age, with an ASIR of 6.2 (4.7–7.7) per million children. This ASIR was not significantly different than that of Egypt, Morocco, Israel, Spain, or France. It was slightly higher than the ASIR of the United States, the United Kingdom, and Germany and markedly higher than for Asia and South Africa. In Africa and much of Asia, early childhood EBV exposure predominates, with nearly all children being infected by 5 years of age. In Sulaimani, just over 50% of children were EBV seropositive at 3 years old and 90% seropositivity was reached at 15 years of age. In Europe and North America, seropositivity is commonly delayed until adolescence or young adulthood and adult predominates over childhood BL.

Conclusion

In the Middle East, childhood BL is relatively common and adult BL is rare. In Sulaimani, EBV seropositivity increases progressively throughout childhood and reaches 92% at mid-adolescence. This may reflect the Mid East more widely. We suggest that the high childhood and low adult BL rates may be a regional effect of a pattern of EBV exposure intermediate between early childhood and adolescent and young adult infections.

Epstein-Barr virus status of sporadic Burkitt lymphoma is associated with patient age and mutational features

Sporadic Burkitt lymphoma (BL) is the most frequent tumour of children and adolescents but a rare subtype of lymphomas in adults. To date most molecular data have been obtained from lymphomas arising in the young. Recently, Epstein-Barr virus (EBV) positive and negative BL in young patients was shown to differ in molecular features. In the present study, we present a large age-overarching cohort of sporadic BL (n = 162) analysed by immunohistochemistry, translocations of MYC proto-oncogene, basic helix-loop-helix transcription factor (MYC), B-cell leukaemia/lymphoma 2 (BCL2) and B-cell leukaemia/lymphoma 6 (BCL6) and by targeted sequencing. We illustrate an age-associated inter-tumoral molecular heterogeneity in this disease. Mutations affecting inhibitor of DNA binding 3, HLH protein (ID3), transcription factor 3 (TCF3) and cyclin D3 (CCND3), which are highly recurrent in paediatric BL, and expression of sex determining region Y-box transcription factor 11 (SOX11) declined with patient age at diagnosis (P = 0·0204 and P = 0·0197 respectively). In contrast, EBV was more frequently detected in adult patients (P = 0·0262). Irrespective of age, EBV-positive sporadic BL showed significantly less frequent mutations in ID3/TCF3/CCND3 (P = 0·0088) but more often mutations of G protein subunit alpha 13 (GNA13; P = 0·0368) and forkhead box O1 (FOXO1; P = 0·0044) compared to EBV-negative tumours. Our findings suggest that among sporadic BL an EBV-positive subgroup of lymphomas increases with patient age that shows distinct pathogenic features reminiscent of EBV-positive endemic BL.

Burkitt lymphoma of the head and neck: An international collaborative study

BACKGROUND

Burkitt lymphoma (BL) is an aggressive B-cell lymphoma with three variants (endemic, sporadic, and immunodeficiency-associated), presenting with specific epidemiological and clinical features. Burkitt lymphoma affects the head and neck region (BLHN) in approximately 10% of cases. The aim of this study was to undertake a comparative analysis of the clinicopathologic and immunohistochemical (IHC) features of BLHN diagnosed in patients from Africa, Guatemala, and Brazil.

METHODS

Cases diagnosed as BLHN were collected from the files of six oral pathology laboratory services (Brazil, South Africa, and Guatemala) and one Brazilian pediatric oncology hospital from 1986 to 2020. Clinicopathological and IHC data, and Epstein-Barr virus (EBV) status by in situ hybridization data for each case were reviewed and described.

RESULTS

Of the 52 cases, BLHN was predominant in pediatric patients [43 (82.69%)] and males [43 (82.69%)], with a mean age of 11.26 ± 9.68 years (range, 1-39 years). Neck and cervical lymph nodes [14 (26.92%)], and involvement of both maxilla and mandible [8 (15.38%)], were the most common anatomical sites. Clinically, tumor/swelling [40 (31.25%)], cervical lymphadenopathy [14 (10.94%)], pain [12 (9.38%)], and bone destruction [12 (9.38%)] were frequent findings. All cases showed typical morphological characteristics of BL. IHC profiles included positivity for CD20 [52 (100%)], CD10 [38 (79.17%)], Bcl6 [29 (87.88%)], and c-Myc protein [18 (81.82%)]. EBV was positive in 18 cases (62.07%). The Ki-67 index ranged from 90 to 100%.

CONCLUSION

The clinicopathological and EBV profile of BLHN in South African, Guatemalan, and Brazilian patients is similar.

B cell lymphoma with IRF4 rearrangement: A clinicopathological study of 13 cases

Interferon regulatory factor 4 (IRF4) rearrangement is commonly detected in patients with a range of lymphoproliferative malignancies, including myelomas, large B cell lymphomas and low-grade B cell neoplasms. However, IRF4 rearrangement is generally a relatively rare finding in these latter two cancer types. In the present article, we describe and summarize the clinicopathological and genetic features of 13 cases of B cell lymphoma with IRF4 rearrangement, including 12 cases of large B cell lymphoma and one case of low-grade lymphoma exhibiting such rearrangement. These cases were detected in six females and seven males between 14 and 71 years of age. From a morphological perspective, large B cell lymphoma tumors included in this analysis exhibited large neoplastic cells in diffuse or follicular patterns, while the case of low-grade lymphoma mainly composed of small lymphocytes. All analyzed cases exhibited a split in the IRF4 gene consistent with IRF4 translocation. Three of six analyzed large B cell lymphoma cases harbored IGLL5 mutations. Mutations in SAMHD1 were detected in the low-grade lymphoma with IRF4 rearrangement case. In summary, our results offer further insight into the morphological and molecular heterogeneity of cases of B cell lymphoma exhibiting IRF4 rearrangements.

Inferior prognosis of gastric involvement in patients with gastrointestinal Burkitt Lymphoma

Due to limited information reported on the clinical characteristics and outcomes of Burkitt lymphoma (BL) patients with gastrointestinal (GI) involvement, here we used the Surveillance, Epidemiology, and End Results (SEER) database to perform our study in a population‐based scale. Extranodal GI involvement was categorized into gastric and intestinal primary sites. A total of 477 BL patients with GI involvement extracted from the SEER database between 2004 and 2015 were included in this study, 112 (23.5%) with the stomach and 365 (76.5%) with the intestine. Our study demonstrated that gastric involvement, older age, male gender, black race, advanced‐stage III/IV, no‐chemotherapy, and earlier years of diagnosis were associated with a significantly worse overall survival (OS) in GI BL patients after adjustment in multivariate analysis, whereas marital status did not significantly influence OS. Notably, BL Patients with gastric involvement had a significantly inferior 5‐year OS in both univariate and multivariate analysis, as compared to those with intestinal involvement (37.8% vs. 70.2%; Univariate: HR = 2.637, P < .001; Multivariate: HR = 1.489, P = .016). In subgroup analysis, we demonstrated that gastric BL patients had a consistently worse OS than intestinal patients regardless of gender, clinical stage and year of diagnosis. Hopefully, with the advances in modern therapy, improved survival has been found in BL patients with GI involvement as a whole, specifically those with gastric involvement (HR = 0.529, P = .011) in recent years of diagnosis. In conclusion, despite the improved survival achieved in recent years, the prognosis of BL patients with gastric involvement is still poor. Novel personalized therapies and better access to intensive care remain to be needed.

Epstein-Barr virus-associated B-cell lymphoproliferative disorders and lymphomas: a review

In this review, we focus on B-cell lymphoproliferative disorders (LPDs) and lymphomas associated with Epstein-Barr virus (EBV). In some of these diseases-such as EBV-positive diffuse large B-cell lymphoma (DLBCL), not otherwise specified-virus detection is required for the diagnosis, while in others its detection is not necessary for diagnosis. EBV infection has three main latency patterns (types III, II, and I). Different latency patterns are found in different LPD types and are related to the host immune system status. For each of the LPDs/lymphomas, we discuss the clinical presentation, epidemiology, pathology, immunophenotype, and genetic or molecular basis. We provide data for a better understanding of the relationships among the discussed diseases and other information that can be useful in differential diagnosis. Not included in this review are classic Hodgkin lymphoma and some specific variants of DLBCL, as these entities are discussed in separate reviews in this issue.

Burkitt lymphoma in Iraqi children: A distinctive form of sporadic disease with high incidence of EBV+ cases and more frequent expression of MUM1/IRF4 protein in cases with head and neck presentation

Epstein-Barr virus (EBV)-related lymphoproliferative disorders are relatively common in Iraqi children. Burkitt lymphoma (BL) accounted for 40% of lymphoma cases. The mean age of 125 BL cases was 5.9 ± 3.1 years, and the male-to-female ratio was 3.6:1. Clinical presentation was abdominal in 66% and head and neck in 34%. Bone marrow involvement was higher (P < 0.001) in children with head and neck disease. Tumor cells had MYC translocation (96%) and were CD20⁺ /CD10⁺ /MYC⁺ /BCL2^- . MUM1/IRF4 staining was expressed by a fraction of tumor cells in 19 of 125 cases (15%) and was more frequent (P < 0.007) in head and neck disease (12/42; 29%). EBV-encoded RNA was positive in 100 of 125 (80%) BL cases.