[Steroid receptors in malignant melanomas].

Epidemiological and experimental investigations have led to the hypothesis that the growth of malignant melanoma is induced by hormones. The demonstration of free-hormone binding sites in melanoma tissue may help to determine the validity of this hypothesis, as receptors are necessary for the transformation of hormonal action. The DCC assay with subsequent saturation analysis was used for the demonstration of specific cytoplasmatic binding sites of steroid hormones. The presence of free-cytosolic estrogen-, progesterone- and glucocorticosteroid receptors was investigated in 50 melanoma samples from 46 patients. In 20 of the 50 specimens, free estrogen and progesterone receptors were found. Free-glucocorticosteroid receptors we found in 10 cases. The use of four fold-labeled estradiol (2,4,6,7-[3]-17 beta-estradiol) in the DCC assay produced a false-positive demonstration of free-estrogen receptors. Tyrosinase hydroxylates estradiol at the C2 level of the steroid. Using fourfold labeled estradiol, tritium is separated at the C2 position, thus forming radioactive water in the cytosol which mimics high, free-estrogen binding sites. The use of twofold-labeled estradiol or L-dopa in the experiments with fourfold labeled estradiol produced no false-positive determinations of estrogen receptors. The demonstration of receptors in malignant melanomas was unaffected by the sex of the patient. Also, the type of malignant melanoma, the invasion level, and the prognostic index did not show a correlation with the presence of the various hormone receptors. In metastases, free steroid hormone receptors were detected less often than in the primary tumor.