THE DISTRIBUTION OF CELLULAR ADHESION MOLECULES IN PIGMENTED SKIN-LESIONS

Background. The process of multistep tumor development has been studie d thoroughly in the development of malignant melanomas. The authors in vestigated the expression of cellular adhesion molecules in nevomelano cytic lesions to explore a postulated role of adhesion molecules in ce ll-cell and cell-matrix interactions during tumor development. Methods . Sections of 20 nevocellular nevi, 35 dysplastic nevi, 6 melanomas in situ, and 20 malignant melanomas were investigated with respect to th eir expression of intercellular adhesion molecule-1 (ICAM-1), inducibl e cell adhesion molecule-110 (INCAM-110)/vascular cell adhesion molecu le-1 (VCAM-1), E-selectin, lymphocyte function-associated antigen-1 (L FA-1), and the integrins for very late antigen-(VLA) alpha-(alpha) 2 a nd VLA-alpha 6; for these studies, monoclonal antibodies were used and indirect immunoperoxidase and immunofluorescence staining methods wer e performed. Results. In the transformation from benign to malignant n eoplasms, the expression of ICAM-1 was upregulated strongly. The expre ssion of VLA-alpha 2 on tumor cells increased whereas that of VLA-alph a 6 decreased; these alterations corresponded to changes previously ob served in their ligands within the extracellular matrix. These results were statistically significant. In addition, ICAM-1, INCAM-11O/VCAM-1 , and E-selectin were detected in activated endothelial cells, probabl y as a result of cytokine activation. The ligand for ICAM-1, LFA-1, wa s confined to mononuclear cells. Conclusions. The increase in ICAM-1 a nd VLA-alpha 2 expression and the decrease of VLA-alpha 6 expression m ay, in combination with specific matrix alterations, lead to a change in cell-cell and cell-matrix interaction, thereby contributing to the invasive property of melanocytic tumor cells. The neoexpression of INC AM-11O/VCAM-1 and E-selectin in pigmented skin lesions may play a role in both infiltrative growth and the generation of a host reaction tow ard these tumors.