U2AF1 and myelodysplastic syndrome: According to National Comprehensive Cancer Network (NCCN) guidelines, epigenetic mutations such as TET2, DNMT3A, ASXL1, IDH1/2, and EZH2 commonly occur in MDS; Splicing factor-related mutations such as SF3B1, SRSF2, U2AF1 and ZRSR2 are not specific mutations of MDS but occur more frequently in MDS than in other myeloid tumors.