Mutations are present in 24% to 33% of cases and are associated with leukocytosis and shorter OS.6, 7 Furthermore, ETNK1 gene mutations were found recently in a minority of cases of aCML and CMML.9, 10 Mutational landscape of CMML are already analyzed in large series of patient samples.11, 12ASXL1, SRSF2, and TET2 gene mutations are found frequently in CMML, each in approximately 40% of cases.14 However, none of these mutations are specific for aCML or CMML, even SETBP1 mutations can be found in a subset of CMML cases.15 Here, TET2 is linked to chronic myelomonocytic leukemia.