Steroid-binding proteins in carcinoma of the human male breast.

Receptor sites for a group of four steroid hormones were estimated by competitive binding assay of a biopsy specimen of carcinoma from a male breast. The results indicate that the tissue contained a significant number of binding sites for 17beta estradiol, and probably for dihydrotestosterone and progesterone, but not for testosterone. These preliminary data suggest that, as in the female, certain mammary carcinomas in the male may be under the influence of steroid hormones. Correlation of such data with responses to therapy may help to establish a more rational approach to the treatment of carcinoma of the male breast.