B2M mutational rates vary in specific subtypes of DLBCL: in DLBCL of the testis and the central nervous system, i.e., DLBCL arising in immunoprivileged sites, B2M mutations have been reported to be frequent (103), while in our study on posttransplant DLBCL, no B2M mutations were detected (104). Here, B2M is linked to diffuse large B-cell lymphoma.