Overexpression of cyclin D1 induced by gene transfection promotes proliferation and epithelial mesenchymal transition in SiHa cells.The process is accompanied by up-regulation of CDK4, CDK2, p21, p27 and cyclin E genes.p21 expression increases synchronously with cyclin D1, suggesting a regulatory role in epithelial mesenchymal transition by affecting expression of vimentin in G-3 cells.