DOT1L and neoplasm: As recently more and more research groups devote to explore molecule targeting inhibitors of histone methyltransferase, such as EZH2- H3K27 inhibitor EPZ – 6438 [37] and DOT1L- H3K79 methylation inhibitors EPZ– 5676 [38], it has become a promising target for anti-tumor therapy [39, 40].