Epigenetic modifiers alter the chromatin structure through posttranslational modifications, such as DNA methylation, thereby changing the accessibility to DNA and gene expression. Mutations in epigenetic regulators, such as DNMT3A, IDH1, IDH2, TET2, ASXL1, EZH2, and MLL/KMT2A, are a key part of leukemogenesis. These mutations are believed to promote clonal outgrowth but require subsequent mutational events to initiate leukemic transformation.