U2AF1 and B-cell chronic lymphocytic leukemia: For example, mutations in SF3B1, U2AF1, SRSF2, and zinc finger CCCH-type, RNA-binding motif and serine/arginine-rich 2 (ZRSR2) were found in a variety of hematological malignancies, including myelodysplastic syndromes (MDSs) and chronic lymphocytic leukemia (CLL), and they are mutually exclusive [94].