From adhesion to signalling: Roles of integrins in the biology of human melanoma

Integrins are cell surface heterodimers which act as regulators of adhesion and as signal transducers in normal and neoplastic cells. The expression and function of integrins are subject to change during the neoplastic transformation of melanocytes and the progression of melanoma. The integrin profile of human melanoma is also characterized by marked inter- and intratumour heterogeneity. These processes influence the interaction of melanoma cells with extracellular matrix (ECM) components and with other cell types that express integrin ligands. Integrins on melanoma cells not only act as mediators of adhesive interactions but also act as signalling molecules. The signal transducing function of integrins plays a role in a number of biological responses of melanoma cells to ECM-derived stimuli, including production of proteolytic enzmes, invasion of basement membranes, expression of genes and proliferation.