Malignant melanoma and melanocortin 1 receptor.

The conventional chemotherapeutic treatment of malignant melanoma still remains poorly efficient in most cases. Thus the use of specific features of these tumors for development of new therapeutic modalities is highly needed. Melanocortin 1 receptor (MC1R) overexpression on the cell surface of the vast majority of human melanomas, making MC1R a valuable marker of these tumors, is one of these features. Naturally, MC1R plays a key role in skin protection against damaging ultraviolet radiation by regulating eumelanin production. MC1R activation is involved in regulation of melanocyte cell division. This article reviews the peculiarities of regulation and expression of MC1R, melanocytes, and melanoma cells, along with the possible connection of MC1R with signaling pathways regulating proliferation of tumor cells. MC1R is a cell surface endocytic receptor, thus considered perspective for diagnostics and targeted drug delivery. A number of new therapeutic approaches that utilize MC1R, including endoradiotherapy with Auger electron and α- and β-particle emitters, photodynamic therapy, and gene therapy are now being developed.