DNMT1 and myelodysplastic syndrome: Azacytidine and decitabine were approved in the early 2000s for the treatment of myelodysplastic syndrome (MDS), acute myeloid leukemia (AML), and chronic myelomonocytic leukemia.650 The anti-cancer activities of the DNMT inhibitors involve both directly targeting tumor cells and enhancement of antitumor immunity.