The MLL/WDR5 protein-protein interaction inhibitor MM-401, compared with its enantiomer control MM-NC-401, suppresses histone H3K4 methyltransferase activity and reduces oncogenic gene transcription, resulting in MLL-rearranged leukemia cell growth inhibition, cell cycle arrest, myeloid differentiation and apoptosis without general toxicity to normal cells (Figures 2, 3; Table 2) (36). This evidence concerns the gene WDR5 and leukemia.