RUNX1 and acute myeloid leukemia: The second overall most frequently mutated gene in this s-AML cohort is RUNX1. Out of the ninety-three s-AML, twenty-nine (31%) carry RUNX1 mutations and twenty-five co-occur with one or more of the eight specific mutations, especially with ASXL1 and SRSF2. RUNX1 cannot be categorized as s-AML-specific mutated gene because of its high prevalence in de novo AML.