RUNX1 mutations account for about 10-15% of all somatic mutations that have been detected in MDS [21,35]. The incidence of RUNX1 mutations in CMML and chronic myelogenous leukemia (CML) is even higher, ranging from 32.1% to 37%, respectively [36]. RUNX1 mutations have also been reported in 14% of patients with MPN, 15.6% of patients with acute lymphoblastic leukemia (ALL), and 10.3-37.5% of AML patients. This evidence concerns the gene RUNX1 and chronic myelogenous leukemia, BCR-ABL1 positive.