U2AF1 and B-cell chronic lymphocytic leukemia: Mutations in the U2AF1 gene have been detected in several hematological malignancies, including myelodysplastic syndromes (MDS) [18,27], chronic lymphocytic leukemia (CLL) [28], acute myeloid leukemia (AML) [29], and, in solid tumors, including breast cancer [30], lung adenocarcinoma [23], as well as in other malignancies, albeit at lower rates.