Azacitidine, a DNMT inhibitor failed to fully eradicate the leukaemic progenitor cell populations in patients with AML and MDS (Craddock et al., 2013), and decitabine, also a DNMT inhibitor only achieved in complete remission in 14% of MDS, 7% of AML and 10% of CMML patients (Helbig et al., 2019). The gene discussed is DNMT1; the disease is chronic myelomonocytic leukemia.