Adhesion molecule profile and malignancy of melanocytic lesions

The ability of melanoma cells to metastasize is largely dependent upon cell surface molecules that mediate cell-matrix and cell-cell interactions. Our aim was to investigate the expression of such molecules (adhesion molecules) on tissue sections of a series of melanocytic lesions in different stages of tumour progression. Four common naevi, four congenital naevi, four dysplastic naevi, three Spitz naevi, 20 primary melanomas and 15 metastatic melanomas were tested with an alkaline phosphatase/anti-alkaline phosphatase technique and a panel of monoclonal antibodies directed toward different alpha subunits of VLA receptors, beta 1, VNR-alpha and beta 3 subunit, and CD44 hyaluronate receptor. Only metastatic melanomas expressed the alpha 4 subunit, and only thick primary melanomas and metastases expressed the beta 3 subunit. The alpha 6/beta 1 chain was expressed at significantly higher levels on benign lesions, and a trend towards increased expression of alpha 2 and alpha 3 subunits was found in malignant versus benign lesions. Our results show that the pattern of integrin expression changes in melanocytic lesions along with malignant transformation.