Some high-frequency mutations, such as mutations in KMT2D, TP53, CD79B, CARD11, EZH2, and MYD88, play important roles in lymphomagenesis (23); presumably, however, additional alterations are also indispensable for the development and characterization of DLBCL (5). The gene discussed is KMT2D; the disease is diffuse large B-cell lymphoma.