Inhibition of the DOT1-like histone H3K79 methyltransferase (DOT1L) is regarded as a possible therapeutic strategy, especially in MLL-rearranged AML [186] but also AML with mutations in DNA methyltransferase 3A (DNMT3A) [187,188]. The gene discussed is KMT2A; the disease is acute myeloid leukemia.