EZH2 and breast cancer: Several lines of evidence support a relationship between histone modifications and cancer invasion: overexpression of EZH2, which catalyzes histone H3 lysine 27 trimethylation (H3K27me3), is associated with prostate- and breast-cancer aggressiveness[43-45]; and G9a, which catalyzes histone H3 lysine 9 dimethylation (H3K9me2), promotes lung-cancer invasion[46].