In s-AML samples the authors found 11 recurrent mutations in coding genes: CDH23, NPM1, PTPN11, RUNX1, SMC3, STAG2, TP53, U2AF1, UMODL1, WT1, and ZSWIM4. At least one mutation in a coding gene was observed in patients who progressed to s-AML. The gene discussed is STAG2; the disease is acute myeloid leukemia.