Adhesion receptors in human melanoma progression.

Melanoma often develops from clinically and histologically well-defined precursor lesions. During progression of normal melanocytes to benign nevi, dramatic changes in the expression of adhesion receptors are observed, most notably loss of E-cadherin which mediates adhesion of melanocytes to keratinocytes, and gain of Mel-CAM which predominantly mediates heterotypic adhesion between cells. Major changes in adhesion receptors also occur when cells progress from dysplastic nevi or biologically early radial-growth-phase primary melanomas to biologically late (tumorigenic) vertical-growth-phase primary melanomas. The integrin subunit beta 3 is up-regulated, whereas other integrins such as alpha 6 beta 1 and alpha V beta 1 are down-regulated. This review highlights the major changes in adhesion receptor expression on melanocytes at various stages of tumor progression.