ENDOTHELIAL P-SELECTIN EXPRESSION IS REDUCED IN ADVANCED PRIMARY MELANOMA AND MELANOMA METASTASIS

Some malignant tumors induce a cellular immune response that results i n the formation of an inflammatory infiltrate and subsequent tumor reg ression. The infiltrating leukocytes extravasate from the bloodstream after binding to adhesion receptors on the surface of the endothelium. One of these receptors is the P-selectin molecule (CD62P) that is con stitutively present on normal capillaries. We observed that P-selectin expression is absent from the microvasculature in advanced primary me lanoma and in melanoma metastasis in contrast to benign melanocytic le sions where P-selectin expression was identical to that in normal skin . We suggest that one of the mechanisms by which advanced melanoma les ions evade inflammatory regression operates via a decrease of endothel ial P-selectin expression.