EZH2 is a human homolog of the Drosophila Polycomb-group protein Enhancer of Zeste protein, and contains a SET domain that catalyzes the methylation of histone H3 at lysine 27. Polycomb-group proteins repress gene expression by binding to chromatin and locally altering chromatin structure. EZH2, BMI-1 and SUZ12 are present in the PRC2 and PRC3 protein complexes that function as mediators of epigenetic transcriptional silencing. Deregulation of EZH2 is linked to a variety of cancers.
