Analysis of the sequential order of acquisition of SETBP1 mutations and cytogenetic aberrations as well as mutations in ASXL1 and TET2 was performed in 22 MDS/CMML cases in transformation to AML: 15 cases (68.2%) presented mutations in at least one of the three genes during the course of the disease, four cases showed the acquisition of SETBP1 mutations during leukemic evolution, in one case the SETBP1 mutation was acquired before harboring the i(17)(q10) marker. This evidence concerns the gene TET2 and chronic myelomonocytic leukemia.