Laminin-induced signaling in tumor cells.

Laminin is the main non-collagenous glycoprotein found in the basement membrane. The various laminin isoforms are involved in many physiological and pathological processes, including cancer dissemination. The interaction of cancer cells with laminin was identified as a key event in tumor invasion and metastasis. Laminin effects are mediated by laminin receptors that are divided into two groups: integrin and non-integrin receptors. Activation of a specific signal transduction pathway in the cell depends on various factors and may be altered when normal tissue becomes neoplastic. Laminin signals via multiple signal transduction pathways involving various components such as G-proteins, intracellular calcium, phospholipase D, mitogen activated protein kinases, phosphatases, focal adhesion kinase, small GTPases of the Rho family, and cytoskeleton components. This review focuses on the role of laminin in tumor progression, its signaling via the non-integrin 67kDa laminin receptor and via integrins and the reciprocal relations between these receptors in certain tumors.