MYD88 and aneurysmal bone cyst: Another important study, by Chapuy et al. [32], defined five subtypes, including two ABC-DLBCL groups, one with lower risk and a possible marginal zone origin (C1, with BCL6 translocations and mutations in NOTCH2), and the other a high-risk group (C5) featuring a high frequency of cases with mutations in MYD88, CD79B, and PIM1; they also described two distinct subsets of GCB-DLBCLs with favorable (C4) and poor outcomes (C3), and an ABC/GCB-independent group (C2) with biallelic inactivation of TP53, CDKN2A loss, and associated genomic instability [32].