Sex steroid receptor analysis in human melanoma

Melanomas from 20 patients were evaluated for estrogen and progesterone receptors. No restriction as to patient's age, sex, race, or menstrual status was made. Fifteen of the tumors were melanin producing. Of the 20 tumors examined, seven contained more than 3 fm/mg protein of specifically inhibitable estrogen binding. None of the tumors reported here demonstrated either a 4S or 8S binding protein as shown by sucrose density gradient analysis. All tumors in which estradiol binding was observed were melanin producing, whereas none of the amelanotic melanomas (five tumors) bound this steroid. Purified tyrosinase appeared to mimic the estrogen binding detected in melanoma cytosols, as demonstrated with the dextran-coated charcoal technique. Although the binding of estradiol to tyrosinase was inhibited by DOPA, the binding of estradiol to estrogen receptor preparations was not. These studies represent an extensive of previous studies of sex steroid binding in melanomas and suggest that gradient analysis and DOPA inhibition studies should be included in the evaluation of the estrogen binding phenomenon in human melanoma.