SNAI1 and cancer: To colonize a distant secondary site, cancer cells undergo epithelial-mesenchymal transition (EMT) characterized by the suppression of epithelial markers E-cadherin and EpCAM and by the expression of mesenchymal markers such as Snail1/2, Twist1/2, vimentin and N-cadherin, associated with the acquisition of migratory capacity pivotal for invasion and metastasis [5,6,7].