EPZ004777, the first SAM-competitive inhibitor of DOT1L, was able to kill biphenotypic (mixed-lineage) leukemia (MLL)-rearranged leukemia cells and prolong the survival time of mice with MLL-rearranged leukemia, but it had little killing effect on non-MLL translocated cells (Daigle et al., 2011; Chen et al., 2013a). This evidence concerns the gene DOT1L and leukemia.