Mutations in MPEG1 have been described in DLBCL1 with the overall rate of mutations somewhat variable across studies. MPEG1 is one of a number of genes affected by aberrant somatic hypermutation in B-cell lymphomas, which complicates the interpretation of mutations at this locus. Coding and non-coding MPEG1 mutations are a feature of the MCD genetic subgroup of DLBCL.