For over 40 years, the most efficient DNMT inhibitor has been 5-aza-dC (decitabine), successfully used in the clinic to treat Myelodysplasia, Acute Myeloid Leukemia (AML), and Chronic Myeloid Leukemia (CML). Here, DNMT1 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.