Diagnosis of ‘double hit’ diffuse large B-cell lymphoma and B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and Burkitt lymphoma: when and how, FISH versus IHC

Abstract

Learning Objective• To know the criteria being used for DHL and DE large B-cell lymphomas and the differences and similarities between these 2 groups of lymphomas

Introduction to a review series: the 2016 revision of the WHO classification of tumors of hematopoietic and lymphoid tissues

“…28 Of note, there are critical aspects of the revision of lymphoid neoplasms besides the molecular advances, and these include the ALK 2 anaplastic large-cell lymphoma arising in association with breast implants, 29 and the indolent T-cell lymphoproliferative disorder of the gastrointestinal tract. 30 The value of combining clinical, pathological, and genetic data for defining real diseases As shown in Figure 2, one of the best examples of disease-defining genetic lesion is the 5q deletion responsible for the MDS with isolated del(5q).…”

MYC as therapeutic target in leukemia and lymphoma

“…47,48 Double hit/triple hit lymphomas refers to those aggressive lymphomas which have simultaneous MYC with BCL2 and/or BCL6 rearrangements. The phenotype of these lymphomas is heterogeneous, sometimes having a DLBCL appearance (2%-12%) while others have a BCLU phenotype (32%-78%), 47 but they all show an aggressive course and appear to be resistant to conventional chemotherapy regimens. New therapeutic approaches using small molecule inhibitors that target MYC and BCL2 are currently under investigation.…”

“…46 MYC rearrangement predicted an inferior outcome in aggressive lymphomas in most studies, but it is not yet entirely clear if this is due to the MYC rearrangement itself or because 50%-80% of MYC-translocated DLBCL cases harbor dual or even triple translocations also targeting BCL2 and/or BCL6. [45][46][47] The prognostic implication of MYC in those patients is difficult to establish since the diagnostic, phenotypic, and cytogenetic criteria, together with therapeutic approaches are very heterogeneous in the different published series. 47 An increasing interest on the "double-expressor" (DE) large B-cell lymphomas, defined by most groups to have approximately 40% MYC and 50%-70% BCL2 cells by immunohistochemistry has been recently described.…”

“…[45][46][47] The prognostic implication of MYC in those patients is difficult to establish since the diagnostic, phenotypic, and cytogenetic criteria, together with therapeutic approaches are very heterogeneous in the different published series. 47 An increasing interest on the "double-expressor" (DE) large B-cell lymphomas, defined by most groups to have approximately 40% MYC and 50%-70% BCL2 cells by immunohistochemistry has been recently described. These lymphomas have more frequently a non-GCB phenotype and whether the identification of these lymphomas helps to prognostically stratify aggressive lymphomas is not clear yet.…”

“…These lymphomas have more frequently a non-GCB phenotype and whether the identification of these lymphomas helps to prognostically stratify aggressive lymphomas is not clear yet. 47 Lymphomas with plasmablastic differentiation include a variety of lymphomas which show a plasmatic gene expression profiling (with upregulation of PRMD1/BLIMP1 and XBP1). All of these together constitute aggressive lymphomas with very poor response to conventional treatments.…”