In atypical CML, lacking the BCR/ABL fusion, recurrent SETBP1 mutations are found in 17/70 cases, some of which abrogate a site for ubiquitination, resulting in increased amounts of SETBP1 and SET protein, lower PP2A activity, and higher proliferation rates (136). Here, SETBP1 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.