Conversely, the pre-B ALL-derived Nalm-6 cell line (4) is the most commonly used B-cell line model for SF3B1 mutation, despite SF3B1 being recurrently mutated in chronic lymphocytic leukemia (CLL; ref. 16), a mature B malignancy. The gene discussed is SF3B1; the disease is B-cell chronic lymphocytic leukemia.