[Histochemical and biochemical assays of estrogen receptors in breast cancer and significance of endocrine therapy].

Estrogen receptors (ER) in breast cancer patients were determined histologically with estradiol-BSA-FITC and biochemically both by sucrose density gradient and dextran coated charcoal methods. Either 8 S or 4 S ER was found clinically to be related to estrogen dependency. ER-positive cells were in clumps or intermixed with ER-negative cells in cancer tissue, which may be one of the reasons for the fact that surgical ablation of breast cancer patients rarely resulted in complete regression of tumors. High dose administration of Hexestrol of Medroxyprogesterone acetate was occasionally effective for ER-negative human and rat breast cancer, which suggests that there is another endocrinological tumor suppressing mechanism besides the mechanism involving the estrogen-ER system.