The frequency of poor prognosis mutations, as defined in CPSS molecular scoring system, such as ASXL1, SETBP1, RUNX1 and NRAS, was higher in CMML than in CMML-RS/SF3B1, which may explain the poorer prognosis of the former group. This evidence concerns the gene ASXL1 and chronic myelomonocytic leukemia.