SF3B1 and myelodysplastic syndrome: About 20-28% of all MDS patients harbor SF3B1 mutation (5, 8, 9) and a much higher occurrence rate of mutations has been detected in MDS with ring sideroblasts (MDS-RS), such as 64~83% in MDS-RS with single lineage dysplasia (MDS-RS-SLD) and 57~76% in MDS-RS with multiple lineage dysplasia (MDS-RS-MLD) (5, 9–11).