SNAI2 and cervical cancer: To further investigate the function of Slug in the regulation of cell motility and distant metastasis in human cervical cancer cells, exogenous Slug was stably overexpressed by transfection of a Slug recombinant plasmid in SiHa cells (Fig. 1a, SiHa-Vec, SiHa-Slug-2 and SiHa-Slug3) and HeLa cells (Fig. 1c, HeLa-Vec, HeLa-Slug-6 and HeLa-Slug-8).