Epithelial-mesenchymal transition in head and neck cancer

Metastasis is one of the most important factors in the prognosis and choice of treatment strategy of patients with head and neck squamous cell carcinoma (HNSCC). In order for dissemination to take effect, tumor cells must segregate themselves from their primary tumor site and migrate into the blood or lymphatic vessels. To detach from the primary tumor, cells have to disrupt cell-cell adhesion, remodel of the cytoskeleton, change in cell-matrix adhesion and finally return to their original condition. This temporary and reversible process is known as the epithelial-mesenchymal transition (EMT). EMT is a dynamic cellular process in which epithelial cells acquire mesenchymal features and suggested to play an important role during cancer invasion and metastasis. With the recent explosion of knowledge on EMT in carcinogenesis, EMT has become an interesting target for anticancer therapy. This review article first highlights at the biochemical changes that take place around the cell membrane called cadherin switching during EMT and looks at the current literature on EMT in HNSCC. Understanding the mechanism of EMT will provide insight to the metastasis of HNSCC and may lead to the development of novel anti-cancer therapeutics.