| Epithelial-mesenchymal transition (EMT) is a process whereby tightly-interacting and immotile epithelial cells acquire the phenotype of loosely-adherent and motile mesenchymal cells. EMT not only facilitates morphogenesis during embryonic development but also promotes invasion and metastasis in tumors. Pathological EMT is associated with E-cadherin repression, which has been shown to contribute to tumor progression. Several oncogenic pathways (TGF beta, Wnt/ beta-catenin, integrins, and Notch etc.) have been reported to induce EMT via cytoskeleton rearrangement and activation of E-cadherin repressors, including Snail, Slug, SIP1, ZEB1, and TCF3.