Multiple steroid receptors in male breast carcinomas.

Specific cytosol receptors for estradiol, progesterone and dihydrotestosterone were detected in human male breast carcinomas. Competition studies with excess unlabelled steroids showed that the receptors were distinct binding proteins. The properties and binding specificity of the estradiol receptor in a male breast carcinoma were very similar to those found in female breast tumors. The possible clinical significance of the presence of steroid receptors in male breast tumors is discussed.