DLBCL : Molecular Genetics
Immunoglobulin heavy- and light-chain genes are clonally rearranged in diffuse large B-cell lymphomas (DLBCL). The immunoglobulin heavy-chain variable region gene is hypermutated. BCL2 and BCL6 genes are rearranged in 20% and 30% of cases respectively. BCL6 is mutated in 70% cases. MYC (8q24) translocation is seen in about 10% of cases, usually fused to a non-immunoglobulin gene in contrast to Burkitt lymphoma. Association with Epstein-Barr Virus (EBV) is seen in <10% of immunocompetent hosts with DLBCL. It is more frequent in anaplastic and plasmablastic variants, in the elderly, and in immunocompromised patients. The image shows a DLBCL with mostly centroblasts and a few lymphocytes.