Clinical and molecular characterization of TP53-mutant acute lymphoblastic leukemia in adults.

TP53-mutant acute lymphoblastic leukemia (ALL) in adults is a high-risk subtype with poor outcomes, yet its molecular landscape and clinical implications remain incompletely defined. In this multi-institutional study of 830 adult ALL patients treated at eight academic centers between 2010 and 2024, we demonstrated that TP53 mutations are independent predictors of inferior overall survival in both B-ALL (median, 1.9 vs 5 years) and T-ALL (1.6 vs 9.5 years), irrespective of age, biologic disease subtype, or therapy. Genomic profiling revealed that >90% of TP53 mutations were DNA-binding domain missense variants, frequently co-occurring with hypodiploidy in B-ALL and NOTCH1/FBXW7 mutations in T-ALL. Unlike myeloid malignancies, biallelic TP53 mutations did not worsen outcomes, and variant type (missense vs truncating) did not influence survival. TP53-mutant B-ALL exhibited higher CD20 positivity than TP53-wild type B-ALL (65% vs 31%) but had inferior responses to conventional chemotherapy. Novel immunotherapies (e.g., inotuzumab/blinatumomab) or venetoclax-containing combination regimens improved remission rates, yet relapses were common, often with CD19/CD20/CD22 loss (triple-negative) or acquisition of new mutations. Allogeneic transplantation in first remission trended toward survival benefit (median, 3.3 vs 2.2 years). These findings underscore TP53-mutant ALL as a distinct, chemo-resistant entity necessitating tailored approaches, with antigen escape highlighting challenges of immunotherapy durability.