DOT1L and leukemia: Another DOT1L inhibitor, SYC-522, effectively delayed the progression of MLL in the preclinical phase by suppressing H3K79 methylation and reducing the expression of two important leukemia-related genes, HOXA9 and MEIS1. Additionally, SYC-522 significantly reduces the expression of CCND1 and BCL2L1, which are important regulators of the cell cycle and anti-apoptotic signaling pathways (49) (Table 1).