The A53 subtype is enriched of ABC DLBCL and is characterized by TP53 mutations and deletions, with extensive aneuploidy, plus deletions of the B2M locus, amplifications of CNPY3 (6p21), 6q losses (TNFAIP3 and PRDM1), gain/amplification of 3q (NFKBIZ) and BCL2 amplifications. The gene discussed is TP53; the disease is aneurysmal bone cyst.