Indeed, approximately half of the subset #2 patients carry SF3B1 mutations (41, 48, 49), in contrast with patients belonging to other aggressive CLL subsets, namely #1 and #8 (4.6% and 0%, respectively) or non-subset CLL, where such mutations are present in 5%–8% of cases (48). The gene discussed is SF3B1; the disease is B-cell chronic lymphocytic leukemia.