KMT2D and diffuse large B-cell lymphoma: To determine the biological function of KMT2D mutations, germinal center B-cell (GCB) DLBCL cell line (SU-DHL-4) and activated B-cell (ABC) DLBCL cell line (U-2932) were engineered to express a fragment of KMT2D (amino acid 4839-5537, containing SET domain for wild-type, KMT2DC5092R, KMT2DG5182fs, KMT2DW5395X and KMT2DR5432Q) protein.