As oncogenes, EZH2 gain-of-function mutations (Y641, A682, and A692) in catalytic SET domains amplified H3K27 methylation, which in turn inhibited the differentiation of plasma cells, promoting oncogenesis in B-cell lymphoma.363,397 These mutations were discovered in 22% of DLBCLs, 10% of BLs, and 4% of primary mediastinal B-cell lymphomas. The gene discussed is EZH2; the disease is B-cell non-Hodgkin lymphoma.