Antigenic phenotype of pigment cell lesions: a study of melanoma, its precursor lesions and heterogeneity in metastatic melanoma.

Expression of surface antigens on cells comprising malignant, dysplastic, and benign pigment cell lesions has been evaluated in situ using an avidin-biotin immunohistologic technique. We have demonstrated expression of HLA-DR, beta 2-microglobulin, and 2 melanoma-associated antigens (MAA) in a range of benign and malignant lesion, and have confirmed the close association of HLA-DR and MAA on malignant lesions. In addition, 5 subcutaneous lesions removed at the same time from one individual were evaluated. Clinical and histologic appearance differed among lesions although the antigenic patterns were similar.