KRAS and myelodysplastic syndrome: Additional molecular abnormalities were detected in 19/31, 10/12 and 12/18 patients in Groups 1, 2 and 3, respectively, with 6/31, 2/12 and 6/18 carrying MDS-related mutations and 5/31, 1/12 and 0/18 carrying NRAS or KRAS mutations.