Clinical and pathological features of Burkitt lymphoma showing expression of BCL2--an analysis including gene expression in formalin-fixed paraffin-embedded tissue

Burkitt lymphoma

Burkitt lymphoma is a mature aggressive B-cell neoplasm with distinctive clinical and morphologic features, a germinal center B-cell immunophenotype, a high proliferation index and MYC rearrangement with an immunoglobulin gene partner. Initially described in equatorial Africa by a surgeon, Denis Burkitt, African (endemic) Burkitt lymphoma was the first neoplasm shown to be associated with a virus, Epstein-Barr virus (EBV), and the first neoplasm shown to be associated with a chromosomal translocation, IGH::MYC. In this article, we provide a brief historical introduction of Burkitt lymphoma, followed by a review of all aspects of this neoplasm including pathogenesis, clinical presentation, morphology, immunophenotype, cytogenetics and molecular findings. We also provide recent updates of this entity, including advances in our understanding of molecular pathogenesis of Burkitt lymphoma and the recent proposal in the current World Health Organization classification that the traditional epidemiologic variants of Burkitt lymphoma are better replaced by presence or absence of EBV infection. We also discuss the differential diagnosis of Burkitt lymphoma and how this neoplasm can be distinguished from reactive conditions and other aggressive B-cell lymphomas/leukemias. Given its very rapid growth and the unique treatment approach employed to treat these patients, it is important to recognize Burkitt lymphoma to facilitate appropriate therapy.

Ki-67 as a Marker to Differentiate Burkitt Lymphoma and Diffuse Large B-cell Lymphoma: A Literature Review

Burkitt lymphoma (BL) is a form of non-Hodgkin's lymphoma (NHL) that is characterized by high aggressiveness and arises from the germinal center of B cells. The prevalence of BL in adulthood is less than 5%. However, it encompasses 40% of all childhood NHL. Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma. It accounts for approximately 25% of all NHL cases worldwide. The differentiation between BL and DLBCL is more clear in theory than in daily practice. However, it is important because it implies different treatments. Compared to the other indolent small cell lymphomas, DLBCLs and BLs show higher Ki-67 index values. The Ki-67 levels in DLBCL typically range from 40% to 90%, while BL has a high Ki-67 positivity, nearing 100%. The aim of this article is to explore and review the function of Ki-67 as a differential marker for BL and DLBCL. An all-language literature search was conducted on MEDLINE, Cochrane, Embase, and Google Scholar until March 2024. The following search strings and Medical Subject Heading (MeSH) terms were used: "Ki-67," "Burkitt lymphoma," and "diffuse large B-cell lymphoma." We comprehensively reviewed the literature on BL, DLBCL, and the Ki-67 marker.

Childhood and Adolescent Relapsed/Refractory Aggressive B-Cell Lymphomas With t(8;14) and BCL2 Expression, Burkitt Lymphoma Versus Diffuse Large B-Cell Lymphoma: A Diagnostic Challenge

We present 2 diagnostically challenging cases of pediatric/adolescent relapsed/refractory aggressive mature B-cell non-Hodgkin lymphoma (B-NHL) within the spectrum of Burkitt lymphoma and diffuse large B-cell lymphoma and illustrate the different therapeutic regimens that are employed for pediatric and adult cancer centers. Both cases displayed varying-sized lymphoma cells with occasional single prominent nucleoli and heterogeneous BCL2 expression. Cytogenetics revealed complex karyotypes with t(8:14)(q24.2;q32) and IGH::MYC rearrangement by FISH. Next generation sequencing revealed deleterious TP53 and MYC mutations. We concluded that both could be diagnosed as "DLBCL-NOS with MYC rearrangement" using the current pathologic classifications, 2022 International Consensus Classification (ICC) and World Health Organization Classifications of Haematolymphoid Tumors (WHO-HAEM5). This report illustrates diagnostic challenges and treatment dilemmas that may be encountered, particularly for adolescent and young adults (AYA).

Human leukocyte antigen (HLA) class I expression on Hodgkin-Reed-Sternberg cells is an EBV-independent major determinant of microenvironment composition in classic Hodgkin lymphoma

Hodgkin-Reed-Sternberg cells (HRSCs) in classic Hodgkin Lymphoma (HL) frequently lack expression of human leukocyte antigen class I (HLA-I), considered to hamper activation of cytotoxic T cells in the tumor microenvironment (TME). Here, we demonstrate HLA-I expression on HRSCs to be a strong determinant of TME composition whereas expression of HLA-II was associated with only minor differential gene expression in the TME. In HLA-I-positive HL the HRSC content and expression of CCL17/TARC in HRSCs are low, independent of the presence of Epstein-Barr virus in HRSCs. Additionally, HLA-I-positive HL shows a high content of CD8+ cytotoxic T cells. However, an increased expression of the inhibitory immune checkpoint LAG3 on CD8+ T cells in close proximity to HRSCs is observed. Suggesting interference with cytotoxic activity, we observed an absence of clonally expanded T cells in the TME. While HLA-I-positive HL is not associated with an unfavorable clinical course in our cohorts, they share features with the recently described H2 subtype of HL. Given the major differences in TME composition, immune checkpoint inhibitors may differ in their mechanism of action in HLA-I-positive compared to HLA-I-negative HL.

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.

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

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

Improving outcomes of childhood and young adult non-Hodgkin lymphoma: 25 years of research and collaboration within the framework of the European Intergroup for Childhood Non-Hodgkin Lymphoma

The European Intergroup for Childhood Non-Hodgkin Lymphoma (EICNHL) was established 25 years ago with the goal to facilitate clinical trials and research collaborations in the field both within Europe and worldwide. Since its inception, much progress has been made whereby major improvements in outcomes have been achieved. In this Review, we describe the different diagnostic entities of non-Hodgkin lymphoma in children and young adults describing key features of each entity and outlining clinical achievements made in the context of the EICNHL framework. Furthermore, we provide an overview of advances in biopathology with an emphasis on the role of biological studies and how they have shaped available treatments. Finally, for each entity, we describe future goals, upcoming clinical trials, and highlight areas of research that require our focus going forward.

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.

Venetoclax enhances the efficacy of therapeutic antibodies in B-cell malignancies by augmenting tumor cell phagocytosis

Immunotherapy has evolved as a powerful tool for the treatment of B-cell malignancies, and patient outcomes have improved by combining therapeutic antibodies with conventional chemotherapy. Overexpression of antiapoptotic B-cell lymphoma 2 (Bcl-2) is associated with a poor prognosis, and increased levels have been described in patients with "double-hit" diffuse large B-cell lymphoma, a subgroup of Burkitt's lymphoma, and patients with pediatric acute lymphoblastic leukemia harboring a t(17;19) translocation. Here, we show that the addition of venetoclax (VEN), a specific Bcl-2 inhibitor, potently enhanced the efficacy of the therapeutic anti-CD20 antibody rituximab, anti-CD38 daratumumab, and anti-CD19-DE, a proprietary version of tafasitamab. This was because of an increase in antibody-dependent cellular phagocytosis by macrophages as shown in vitro and in vivo in cell lines and patient-derived xenograft models. Mechanistically, double-hit lymphoma cells subjected to VEN triggered phagocytosis in an apoptosis-independent manner. Our study identifies the combination of VEN and therapeutic antibodies as a promising novel strategy for the treatment of B-cell malignancies.

Anti-apoptotic MCL1 Protein Represents Critical Survival Molecule for Most Burkitt Lymphomas and BCL2-negative Diffuse Large B-cell Lymphomas

The pro-survival MCL1 protein is overexpressed in many cancers, including B-cell non-Hodgkin lymphomas (B-NHL). S63845 is a highly specific inhibitor of MCL1. We analyzed mechanisms of sensitivity/resistance to S63845 in preclinical models of diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma. Annexin V-based cytotoxic assays, Western blot analysis, protein co-immunoprecipitation, and cell clones with manipulated expression of BCL2 family proteins were used to analyze mechanisms of sensitivity to S63845. Experimental in vivo therapy with S63845 and/or venetoclax was performed using patient-derived xenografts (PDX) of treatment-refractory B-NHL. A subset of DLBCL and majority of Burkitt lymphoma cell lines were sensitive to S63845. The level of BCL2 protein expression was the major determinant of resistance to S63845: BCL2 serves as a buffer for pro-apoptotic proteins released from MCL1 upon exposure to S63845. While BCL2-negative lymphomas were effectively eliminated by single-agent S63845, its combination with venetoclax was synthetically lethal in BCL2-positive PDX models. Concerning MCL1, both, the level of MCL1 protein expression, and its occupational status represent key factors mediating sensitivity to S63845. In contrast to MCL1-BIM/BAK1 complexes that prime lymphoma cells for S63845-mediated apoptosis, MCL1-NOXA complexes are associated with S63845 resistance. In conclusion, MCL1 represents a critical survival molecule for most Burkitt lymphomas and a subset of BCL2-negative DLBCLs. The level of BCL2 and MCL1 expression and occupational status of MCL1 belong to the key modulators of sensitivity/resistance to S63845. Co-treatment with venetoclax can overcome BCL2-mediated resistance to S63845, and enhance efficacy of MCL1 inhibitors in BCL2-positive aggressive B-NHL.

Two Clonally Distinct B-Cell Lymphomas Reveal the Diagnosis of XLP1 in a Male Child and His Asymptomatic Male Relatives: Case Report and Review of the Literature

X-linked lymphoproliferative disease type 1 (XLP1) is a primary immunodeficiency disorder caused by pathogenic variants in the SH2D1A gene (SH2 domain containing protein 1A). Patients with XLP1 may present acutely with fulminant infectious mononucleosis, hemophagocytic lymphohistiocytosis, and/or B-cell non-Hodgkin lymphoma (B-NHL). We report a boy who developed 2 clonally distinct B-NHL 4 years apart and was found to have previously unrecognized XLP1. The report highlights the importance of clonal analysis and XLP1 testing in males with presumed late recurrences of B-NHL, and the role of allogeneic stem cell transplant (allo-SCT) in XLP1 patients and their affected male relatives.

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.

Update on Pediatric and Young Adult Mature Lymphomas

After acute leukemia and brain and central nervous system tumors, mature lymphomas represent the third most common cancer in pediatric patients. Non-Hodgkin lymphoma accounts for approximately 60% of lymphoma diagnoses in children, with the remainder representing Hodgkin lymphoma. Among non-Hodgkin lymphomas in pediatric patients, aggressive lymphomas, such as Burkitt lymphoma, diffuse large B-cell lymphoma, and anaplastic large cell lymphoma, predominate. This article summarizes the epidemiologic, histopathologic, and molecular features of selected mature systemic B-cell and T-cell lymphomas encountered in this age group.

Molecular characterization of Burkitt lymphoma in the breast or ovary

Breast and ovary have been described as rare but typical sites of presentation of Burkitt lymphoma (BL) in females, particularly after puberty. We revised a historic series of 44 lymphomas of the breast or the ovary in women diagnosed between 1973 and 2014 as BL. Fluorescence in situ hybridization (FISH) was applied to all, and array-based copy number analysis as well as expression profiling to a subset of those cases. Of the 42 cases evaluable for FISH, 19 cases showed an IG-MYC translocation but only 9 of those fulfilled the criteria of the current WHO classification for the diagnosis of BL. Those nine cases resembled BL of other sites with regard to molecular features. Our findings along with literature data suggest that breast and ovarian BL (1) seem to be rarer than hitherto assumed, (2) share typical molecular features with other BL, and (3) predominantly affect women in the fertile age.

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.

Function of Deptor and its roles in hematological malignancies

Deptor is a protein that interacts with mTOR and that belongs to the mTORC1 and mTORC2 complexes. Deptor is capable of inhibiting the kinase activity of mTOR. It is well known that the mTOR pathway is involved in various signaling pathways that are involved with various biological processes such as cell growth, apoptosis, autophagy, and the ER stress response. Therefore, Deptor, being a natural inhibitor of mTOR, has become very important in its study. Because of this, it is important to research its role regarding the development and progression of human malignancies, especially in hematologic malignancies. Due to its variation in expression in cancer, it has been suggested that Deptor can act as an oncogene or tumor suppressor depending on the cellular or tissue context. This review discusses recent advances in its transcriptional and post-transcriptional regulation of Deptor. As well as the advances regarding the activities of Deptor in hematological malignancies, its possible role as a biomarker, and its possible clinical relevance in these malignancies.

BCL-2 Proteins in Pathogenesis and Therapy of B-Cell Non-Hodgkin Lymphomas

The ability to inhibit mitochondrial apoptosis is a hallmark of B-cell non-Hodgkin lymphomas (B-NHL). Activation of mitochondrial apoptosis is tightly controlled by members of B-cell leukemia/lymphoma-2 (BCL-2) family proteins via protein-protein interactions. Altering the balance between anti-apoptotic and pro-apoptotic BCL-2 proteins leads to apoptosis evasion and extended survival of malignant cells. The pro-survival BCL-2 proteins: B-cell leukemia/lymphoma-2 (BCL-2/BCL2), myeloid cell leukemia-1 (MCL-1/MCL1) and B-cell lymphoma-extra large (BCL-XL/BCL2L1) are frequently (over)expressed in B-NHL, which plays a crucial role in lymphoma pathogenesis, disease progression, and drug resistance. The efforts to develop inhibitors of anti-apoptotic BCL-2 proteins have been underway for several decades and molecules targeting anti-apoptotic BCL-2 proteins are in various stages of clinical testing. Venetoclax is a highly specific BCL-2 inhibitor, which has been approved by the US Food and Drug Agency (FDA) for the treatment of patients with chronic lymphocytic leukemia (CLL) and is in advanced clinical testing in other types of B-NHL. In this review, we summarize the biology of BCL-2 proteins and the mechanisms of how these proteins are deregulated in distinct B-NHL subtypes. We describe the mechanism of action of BH3-mimetics and the status of their clinical development in B-NHL. Finally, we summarize the mechanisms of sensitivity/resistance to venetoclax.

A long-term retrospective study on sporadic Burkitt lymphoma in chinese population

Burkitt lymphoma (BL), an aggressive malignancy, brings a prognosis varying among children, adolescents, and adults. Most of previous retrospective studies of BL focused on a part of population. This study aimed to find the leading prognostic factors in BL among patients of different age groups. World Health Organization classification of lymphoid neoplasms in 2008 and revision in 2016 were used as diagnostic criteria for BL. We compared the laboratory results and clinical manifestations in 2 age groups by Kaplan-Meier survival analysis. Our study strongly indicated that age >14 years and lactate dehydrogenase >570 U/L were 2 powerful prognostic factors for BL. The results indicated that poor prognosis may be for the poor tolerance and low dose of drugs in adolescents and adults.

Paediatric non-Hodgkin lymphoma - perspectives in translational biology

Exciting advances have been achieved for infants, children and adolescents diagnosed with, and treated for, non-Hodgkin lymphoma (NHL). In spite of these successes, new frontiers are being paved to improve the prognosis for those who relapse or have resistant disease. This review summarizes some of the novel approaches and ideas in NHL monitoring, diagnosis and treatment as discussed at the 5th International Symposium on Childhood, Adolescent and Young Adult Non-Hodgkin Lymphoma on October 22nd-24th 2015 in Varese, Italy.

Molecular genetics of childhood, adolescent and young adult non-Hodgkin lymphoma

Molecular genetic abnormalities are ubiquitous in non-Hodgkin lymphoma (NHL), but genetic changes are not yet used to define specific lymphoma subtypes. Certain recurrent molecular genetic abnormalities in NHL underlie molecular pathogenesis and/or are associated with prognosis or represent potential therapeutic targets. Most molecular genetic studies of B- and T-NHL have been performed on adult patient samples, and the relevance of many of these findings for childhood, adolescent and young adult NHL remains to be demonstrated. In this review, we focus on NHL subtypes that are most common in young patients and emphasize features actually studied in younger NHL patients. This approach highlights what is known about NHL genetics in young patients but also points to gaps that remain, which will require cooperative efforts to collect and share biological specimens for genomic and genetic analyses in order to help predict outcomes and guide therapy in the future.