DETECTION OF PROOPIOMELANOCORTIN-DERIVED ANTIGENS IN NORMAL AND PATHOLOGICAL HUMAN SKIN

We investigated the presence of proopiomelanocortin (POMC) products in sections of skin from normal subjects and patients with neoplastic an d non-neoplastic cutaneous disorders. Antibodies specific against adre nocorticotropin, beta-melanotropin, and beta-endorphin were used for d etection and characterization of cell types bearing POMC peptides. POM C products were not observed in sections of normal skin from the corpo ral (non-scalp) areas (six cases), whereas the hair follicles of scalp skin exhibited positive immunostains that were readily apparent (four cases). POMC products were frequently detected in corporal skin affec ted by diseases (13 of 26 cases), for example, psoriatic keratinocytes , the inflammatory infiltrate in scarring alopecio, nevocytes, the epi thelial cell nests of basal cell carcinoma, and melonoma cells. Furthe r tests were performed in keloids, a primary reactive skin disorder, t o evaluate whether POMC accumulation represented a disease-related phe nomenon or an expression of normal cutaneous reactivity. POMC products were consistently detected (10 of 11 cases) in the keratinocytes and mononuclear cells at keloid lesions. Thus these observations indicate that POMC products may accumulate locally in lesional skin representin g, presumably, a novel cutaneous response to injury. The broad spectru m of POMC products detected suggests that these arise from production in situ (expression of the POMC gene itself) by human skin.