SF3B1 and B-cell chronic lymphocytic leukemia: For instance, lesions in Splicing factor 3B1 (SF3B1) occur in 5–17% of chronic lymphocytic leukemia (CLL) [194] and in up to 46% of chronic myelomonocytic leukemia (CMML) patients [195], respectively, and are implicated in worse prognosis.