Genetic or pharmacological inhibition of DOT1L leads to downregulation of target genes and impaired proliferation, cell cycle, and survival of leukemia cells in leukemias driven by MLL fusion (Okada et al., 2005; Chang et al., 2010; Bernt et al., 2011; Nguyen et al., 2011b; Jo et al., 2011; Deshpande et al., 2013). Here, DOT1L is linked to leukemia.