DCG066 is an inhibitor of lysine methyltransferase G9a. DCG066 can bind directly to G9a and inhibit methyltransferase activity in vitro. DCG066 decreases di-methylation levels of histone H3 lysine 9 ( H3K9Me2 ), inhibits cell proliferation and induces cell apoptosis. DCG066 displays low cytotoxicity in leukemia cell lines with high levels of G9a expression, including K562.