EZH2 and Familial prostate cancer: Moreover, we validated in this study that the roles of EZH2 protein in downregulating these miRNA expression in prostate cancer cells were mediated by its catalysis of the formation of H3K27 trimethylation (H3K27me3) located close to the promoters of genes encoding miR-340-5p, miR-143-3p, and miR-145-5p.