DNMT inhibitors (DNMTis), such as 5-azacytidine and 5-aza-2′-deoxycytidine, have been approved by the United States Food and Drug Administration (FDA) in the treatment of patients with myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) [43–45]. The gene discussed is DNMT1; the disease is acute myeloid leukemia.