As mentioned above, BI-9321, the first selective and potent PWWP inhibitor in NSD family was reported by Bottcher et al. and By superposition of these two cocrystal structures (Figure ), it could be seen that, comparing the binding site of NSD3-PWWP1 domain with the NSD2-PWWP1 domain, the most striking difference is at the vicinity of benzonitrile group of MR837.