Protein S-100 immunostaining as a diagnostic tool for DMBA-induced melanotic lesions

In the present study we demonstrate immunohistochemically the presence of S-100 protein in numerous melanotic and amelanotic lesions (benign, premalignant and malignant) induced in albino guinea-pigs on topical application of the carcinogen. Positive staining was also present in all their amelanotic metastases. We reiterate the value of this stain in the diagnosis of melanomas, in particular amelanotic melanomas.