EXPRESSION OF CATHEPSIN-D IN PRIMARY AND METASTATIC HUMAN-MELANOMA AND DYSPLASTIC NEVI

High levels of cytosolic cathepsin D expression have been associated w ith poop prognosis in breast cancer node-negative patients, In this wo rk, we provide evidence that three cell lines established from human m etastatic melanomas-IIB-MEL-J, IIB-MEL-LES, and IIB-MEL-IAN-express hi gh levels of procathepsin D mRNA, IIB-MEL-J cells secreted into the co nditioned media about 30% of the newly synthesized protein, which was active at acidic pH, Melanoma tumors arising in nude mice after inject ion of the three different cell lines expressed high levels of procath epsin D mRNA, Moreover, 13 human metastatic melanomas expressed variab le levels of procathepsin D mRNA, To study the possible association be tween cathepsin D expression and melanoma development, samples corresp onding to 10 primary tumors, 11 metastatic melanomas, 10 dysplastic ne vi, 27 nevocellular nevi, and normal melanocytes were studied by immun ohistochemistry for cathepsin D-specific staining, We found that cathe psin D was expressed in all of the dysplastic nevi and primary and met astatic melanomas tested but in only 18% of nevocellular nevi (five of 27), whereas normal melanocytes showed no cathepsin D expression, The overall data indicate that cathepsin D is expressed at a high level b y melanoma cells, and because of its expression in preneoplastic lesio ns, it may be associated with melanoma development.