IGHM and diffuse large B-cell lymphoma: In addition, IGHM expressed in naïve B-cells and plasma cells was upregulated in CD5+ patients, whereas MYC mutations, which may arise from an aberrant hypermutation process in DLBCL [49], were almost absent in CD5+ DLBCL patients (only one CD5+ GCB-DLBCL case had MYC mutations).