U2AF1 and acute myeloid leukemia: Spliceosome mutations (such as SRSF2, SF3B1, U2AF1, and ZRSR2), along with driver mutations in the cohesion complex, transcriptions factors (RUNX1), and chromatin modifiers (e.g., ASXL1), define a chromatin-spliceosome molecular subtype of AML (CS-AML).