Mutations in the genes EZH2, BCOR, TP53, or STAG2 are frequently found in s-AML and together with the splicing genes SRSF2, SF3B1, U2AF1, and ZRSR2, they are highly specific for s-AML compared to de novo AML, reflecting its evolution from MDS [5]. Here, U2AF1 is linked to myelodysplastic syndrome.