EZH2 and breast cancer: EZH2 mediates the trimethylation of histone 3 lysine 27 (H3K27me3), which serves as an epigenetic code for subsequent recruitment of PRC1, DNA methyltransferases (DNMTs) and histone deacetylases, resulting in chromatin condensation and transcription suppression.15 In addition, EZH2 can also directly interact with DNMTs and regulate the methylation of EZH2-target genes,16 although these interactions might be cell-type specific.17 Recently, EZH2 has also been functionally linked with BRCA1 in breast cancer.