The mutations associated with a poor prognosis include CD28 mutations in AITL (16); TP63 rearrangement (21), loss of TP53, and loss of PRDM1 (22) in ALK− ALCL; GATA3 (75), TP53, and/or CDKN2A (25) in ALK− ALCL; and alterations in histone methyltransferase genes KMT2A, KMT2B, or KDM6A (82) and FAT1 (29) in PTCL-NOS. Here, FAT1 is linked to mature T-cell and NK-cell non-Hodgkin lymphoma.