Promising examples are the inhibition of the DOT1-like (DOT1L) histone H3K79 methyltransferase with pinometostat (EPZ-5676) in adults with MLL/KMT2A-driven leukemia (NCT02141828) (Stein et al., 2018) or inhibition of histone H3K4 and K9 demethylation by the lysine-specific demethylase 1 (LSD1) inhibitor seclidemstat, currently being assessed in clinical trials to treat refractory Ewing sarcomas (NCT03600649). Here, KMT2A is linked to Ewing sarcoma.