Clinical data and estradiol receptor evaluation in breast cancer biopsies.

To determine the correlation between the response to the estradiol receptor test and some fundamental properties of the tumor and the host, a study was conducted on 337 patients. Primary carcinomas, including lobular carcinomas, and recurrences or metastases are characterized by similar frequencies of response to the estradiol receptor test (68% positive, 26% negative and 6% borderline), while normal breast tissue is characterized by a higher frequency of negative results (3% positive, 71% negative and 26% borderline). Postmenopausal patients show a shift of estradiol receptor levels towards higher values with respect to premenopausal patients. Contemporaneously, an increase in estradiol receptor concentrations with patient age is observed. The clinical stage appears in influence estradiol receptor content only in postmenopausal patients, for whom an increase in the tumor size is accompanied by a decrease in the estradiol receptor levels. The apparent association constant of the receptors assumes values ranging from 1.5 to about 300 X 10(9) M-1 and does not appear to be related to either the type of tumor tissue or to the clinical stage of the tumor, age, or menopausal status of the patients.