Homogeneous immunophenotype and paucity of secondary genomic aberrations are distinctive features of endemic but not of sporadic Burkitt's lymphoma and diffuse large B‐cell lymphoma with MYC rearrangement

Abstract

The present study has compared immunohistological marker expression profiles and genomic imbalances in seven African endemic Burkitt's lymphomas (eBLs) with those in ten European B‐cell lymphomas with MYC rearrangement as shown by fluorescence in situ hybridization (FISH) analysis. eBLs showed a typical histomorphology and a homogeneous immuno‐profile: CD10+, CD38+, CD77+, bcl‐2–, and IgM+. Epstein–Barr virus (EBV) DNA was present in all cases. On comparative genomic hybridization (CGH), only three out of six eBLs showed imbalances (median number of imbalances = 2), with gains on chromosome 17 in two eBLs. The European lymphomas were all highly proliferating, with a Ki‐67 index of at least 90%, and included seven with morphology typical of sporadic Burkitt's lymphoma (sBL) and three immunoblastic diffuse large B‐cell lymphomas with MYC rearrangement (MYCre+DLBCL). In contrast to eBL, the immuno‐profiles of the European lymphomas were less homogeneous and inconsistent for CD10, CD38, CD77, IgM and bcl‐2 expression. EBV DNA was not detected. In five of seven sBLs, CGH showed a higher number of imbalances (median = 6), with recurrent gains on chromosome 1q (3/7) and losses on 12q and 17p (2/7), whereas all three MYCre+DLBCLs had fewer imbalances (median = 4), with gains on 17q in two of three lymphomas. It is concluded that eBL has a homogeneous immunohistology and few secondary genomic aberrations, whereas MYC‐rearranged and highly proliferating European B‐cell lymphomas are a heterogeneous group that includes sBL and a subgroup of diffuse large B‐cell lymphomas. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.