U2AF1 and myelofibrosis: Adverse variants for decreased overall, leukemia- or fibrosis-free survival included SH2B3, SF3B1, U2AF1, TP53, IDH2, and EZH2. Overall survival is impacted by SF3B1/SRSF2 mutations, whereas U2AF1 and SF3B1 mutations may affect myelofibrosis-free survival and TP53 mutations predicted leukemic transformation.