Chapuy et al.14 distinguished five subsets of DLBCL, including two ABC-DLBCL groups, one with low risk and a possible marginal zone origin (C1), and the other a high-risk group (C5) enriched in cases with mutations in MYD88, CD79B, and PIM1; they also described two subsets of GCB-DLBCLs with favorable (C4) and poor (C3) outcomes, and an ABC/GCB-independent group (C2) with biallelic inactivation of TP53, CDKN2A loss, and associated genomic instability. The gene discussed is CDKN2A; the disease is diffuse large B-cell lymphoma.