Emerging Roles of Focal Adhesion Kinase in Cancer

Focal adhesion kinase (FAK) is a cytoplasmic nonreceptor tyrosine kinase that enables activation by growth factor receptors or integrins in various types of human cancers. The kinase-dependent and kinase-independent scaffolding functions of FAK modulate the authentic signaling and fundamental functions not only in cancer cells but also in tumor microenvironment to facilitate cancer progression and metastasis. The overexpression and activation of FAK are usually investigated in primary or metastatic cancers and correlated with the poor clinical outcome, highlighting FAK as a potential prognostic marker and anticancer target. Small molecule inhibitors targeting FAK kinase activity or FAK-scaffolding functions impair cancer development in preclinical or clinical trials. In this review, we give an overview for FAK signaling in cancer cells as well as tumor microenvironment that provides new strategies for the invention of cancer development and malignancy.