Cellular and molecular biology of melanoma

Melanoma cells have surface markers that are expressed differently than in normal melanocytes and nevus cells. Monoclonal antibodies may define a phenotypic map of the various melanocytic lesions and can be used in immunohistopathology and immunoscintigraphy. Monoclonal antibodies directed against melanoma-associated glycoproteins and glycolipids are being tested for therapy. Rearrangements or deletions on chromosome 1, 6, and 7 are the most frequently observed cytogenetic abnormalities. Molecular studies have not given a clear picture. A subset of HRAS alleles has been reported to be associated with melanoma. NRAS activation by point mutation has been found in one fourth of the cases. Allele losses at different loci have been reported. Genetic linkage studies have given conflicting results on the presence of a gene for the melanoma-dysplastic nevus syndrome on the short arm of chromosome 1.