CPI-169 is a highly potent and selective inhibitor of EZH2, demonstrating IC50 values of 0.24 nM for wild-type, 0.51 nM for the Y641N mutant, and 6.1 nM for EZH1. This compound is a valuable chemical probe for epigenetic research, enabling the study of histone methylation roles in cancer biology and other diseases in both cellular and animal models.