Recent studies have demonstrated important roles of miRNAs in cancer, regulating cell cycle,16 differentiation,17,18 metabolism,19 invasion and metastasis,20 as well as apoptosis.21 Recently, we have reported that miR-31 was significantly downregulated in prostate cancer cells and its downregulation resulted in overexpression of antiapoptotic protein E2F6 and resistance to apoptosis.22 Studies by Lin et al.23 have shown that miR-31 is epigenetically silenced in prostate cancer by promoter hypermethylation and histone H3K27 trimethylation. The gene discussed is E2F6; the disease is prostate cancer.