Estradiol receptor activity in tissues of human breast cancer.

Using the method for receptor determination recommended by the EORTC breast, cancer group we found 33.8% of our tissue specimen experimentally estradiol sensitive. No relation could be seen between receptor binding ability of the tumor tissues and lymph node involvement, tumor histology, clinical stages of the disease and menopausal state of the patients, respectively. In most cases primary tumor tissues and tissues of invaded lymph nodes show a corresponding behaviour in relation to estradiol uptake. The differences observed in the effects of various antiestrogenic substances on estradiol binding ability can not be explained at present.