In mesenchymal breast and prostate cancer cells, ectopic expression of OVOL1 or/and OVOL2 can induce mesenchymal–epithelial transition (MET), which is the reverse process of EMT, thereby suppressing cell migration.35 Although OVOL2 has been uncovered to attenuate TGF-β-induced EMT in breast cancer cells,36 the function of OVOL1 in the regulation of TGF-β/BMP signal transduction during breast cancer progression is ill-defined. This evidence concerns the gene TGFB1 and prostate cancer.