Splicing factor 3b subunit 1 mutation patterns and prognostic implications in myelodysplastic syndromes, acute myeloid leukemia, and chronic lymphocytic leukemia: A retrospective study of 1691 cases

BACKGROUND: Splicing factor 3b subunit 1 (SF3B1) mutations have been implicated in hematologic malignancies, but the clinical significance of distinct SF3B1 mutation variants remain unclear. METHODS: The objective of this study was to evaluate clinicopathologic features, mutational profiles, and outcomes of 1691 patients with hematologic malignancies, including myelodysplastic syndromes (MDS; n = 402), acute myeloid leukemia (AML; n = 758), and chronic lymphocytic leukemia (CLL; n = 531). RESULTS: CLL, the most common co-mutated genes were ATM (11 of 45; 24.4%) and TP53 (11 of 45; 24.4%). Kaplan-Meier analysis indicated that the SF3B1 p.K700E variant was significantly associated with improved overall survival (OS) and progression-free survival (PFS) in patients who had MDS (p < .001 and p = .016, respectively) but with worse OS and PFS in those who had AML (p = .006 and p = .006, respectively) compared with those who had wild-type SF3B1. In patients who had CLL, p.I704F was associated with reduced OS (p < .001) and p.K700E was associated with a shorter time-to-first treatment (p = .028) compared with those who had wild-type SF3B1. Multivariable analysis identified p.K700E as an independent protective factor for OS in patients with MDS (p = .048) but as an independent risk factor for both OS and PFS in patients with AML (p = .036 and p = .035, respectively) and for the time to first treatment in patients with CLL (p = .033). CONCLUSIONS: Specific SF3B1 variants should be incorporated into prognostic stratification for hematologic malignancies.