The roles of integrin αvβ6 in cancer.

Integrins are a family of heterodimeric cell surface receptors that are expressed in most cells, where they mediate cell-cell and cell-extracellular matrix (ECM) interactions. Integrin αvβ6 is a heterodimer with αv and β6 subunits. It is epithelial-specific and strongly induced during wound healing, inflammation and carcinogenesis. Integrin αvβ6 is considered to be a prognostic indicator because it is up-regulated in various types of cancers and integrin αvβ6 expression correlates with the survival time of patients. A large body of evidence suggests that integrin αvβ6 is of great significance in tumor progression, as integrin αvβ6 has been demonstrated to modulate numerous malignant behaviors of tumor cells. A number of classic oncogenic signaling pathways are involved in integrin αvβ6-mediated tumor progression. The expression characteristics and vital effects of integrin αvβ6 in the progression of tumors has led studies to focus on integrin αvβ6-targeted tumor imaging and tumor therapy, which have subsequently made integrin αvβ6 a promising target for clinical examination and treatment. This review provides an overview of the current understanding of the roles and underlying mechanisms of integrin αvβ6 in tumors. Furthermore, the common links as well as discrepancies between independent studies are also discussed.