KMT2A and acute myeloid leukemia: It is not clear whether the apparent discrepancy between ALL, with relatively few data on histone modifiers, and acute myeloid leukemia (AML), in which most patients are reported to have mutations in epigenetic modifiers including in particular DNMT3A (DNA methyltransferase 3A), TET2 methylcytosine hydroxylase (Ten-Elevan-Translocation-2) or MLL1 (mixed lineage leukemia 1), is truly related to disease biology or a result of study bias [12,13,14].