P53 plays a crucial role in cell cycle regulation and apoptosis after DNA damage, and its role in tumorigenesis is well-recognized in solid and hematologic malignancies, particularly acute myeloid leukemia (AML) and chronic lymphocytic leukemia (CLL), in which its deregulation represents an important predictor of poor outcome. 3-10 In ALL, TP53 mutations have been poorly investigated, mainly in children, for whom the incidence is low at diagnosis, increases at relapse, and is associated with poor outcome. 8-10 In adult ALL, the few studies performed include mostly relapsed cases and small cohorts of patients. 11, 12 We evaluated 98 newly diagnosed adult ALL cases to address the incidence and prognostic impact of TP53 mutations; in 10 cases, paired material collected at relapse was also available. Sixty-two cases had B-cell ALL (B-ALL) and 36 were TALL. Within B-ALL cases, 25 were BCR-ABL1, 9 MLL/AFF1+ and 4 E2A/PBX1+; within T-ALL cases, 7 were