Defining the role of integrin alphavbeta6 in cancer.

Integrins are a large family of heterodimeric transmembrane receptors that mediate cell-substratum adhesion. alphavbeta6 is an epithelial-specific integrin that is a receptor for the extracellular matrix (ECM) proteins fibronectin, vitronectin, tenascin and the latency associated peptide (LAP) of TGF-beta. Integrin alphavbeta6 is not expressed in healthy adult epithelia but is upregulated during wound healing and in cancer. alphavbeta6 has been shown to modulate invasion, inhibit apoptosis, regulate the expression of matrix metalloproteases (MMPs) and activate TGF-beta1. There is increasing evidence, primarily from in vitro studies, that suggest that alphavbeta6 may actually promote carcinoma progression. In this review we summarize what has been learnt in the past few years about the role of alphavbeta6 in cancer progression.