U2AF1 and myelodysplastic syndrome: In contrast, in MDS, the most frequent mutations directly affect members of the spliceosome, such as SF3B1, SRSF2, U2AF1, and ZRSR2, as well as genes involved in DNA methylation and chromatin remodeling, such as TET2, DNMT3A, IDH1/2, and ASXL1 [34].