Epimutations define heritable changes in gene activity, which, unlike classical gene mutations, are not due to changes in DNA sequence.32, 33 They occur in somatic cells, particularly in tumor suppressor genes.34RB methylation was identified as the first example of epimutation35 and subsequently many other oncogenes have been shown to be methylated in sporadic cancers.36, 37, 38 In this study, we describe that AML patients often reveal aberrant hypermethylation in DNMT3A and the same effect was also observed in AML cell lines. This evidence concerns the gene DNMT3A and acute myeloid leukemia.