Abstract
In order to obtain more information on the interrelationships between cytosol estrogen (ER) and progestin (PR) receptors in breast carcinoma, and their distribution according to age, menopausal status and endocrine parameters of the patients, these receptors were measured in 605 primary and 150 metastatic lesions, and correlated with serum levels of estradiol, progesterone, FSH, LH and prolactin in some of these patients. Measurable estrogen receptor (> 3 fmol/mg cytosol protein) was found in 78.0% and progestin receptor (> 10 fmol/mg cytosol protein) in 60.5% of all the samples studied. The receptors were simultaneously present in 57.2%, estrogen receptor only in 20.8%, progestin receptor only in 3.3%, while both receptors were absent in 18.7% of the whole material. In samples from 253 premenopausal patients, measurable ER was found less frequently (71.1% of cases) and its concentration was lower (39.9 ± 5.1 fmol/mg cytosol protein, mean ± SEM) than in 502 postmenopausal patients (82%; 148.2 ± 11.6 fmol/mg). The frequencies of ER‐positive samples and ER concentration were rather similar in primary and metastatic lesions, whereas PR was more often present (64 versus 47%) and its concentrations significantly higher (151.2 ± 12.5 versus 102.6 ± 21.1 fmol/mg) in primary than in metastatic tumors. When present simultaneously, there was a significant correlation between ER and PR concentrations in both primary and metastatic lesions independent of the menopausal status of the patient. ER concentration correlated significantly with age in both pre‐ and postmenopausal patients, while PR concentration correlated with age only in postmenopausal patients. The group with the highest ER values (above 100 fmol/mg cytosol protein) had a significantly lower serum estradiol concentration that the other patients. Serum estradiol values had a significantly positive correlation with cytosol PR content in the samples with a measurable PR. Serum progesterone, FSH, LH and prolactin did not correlate with tumor ER or PR concentrations. We conclude that concomitant assays of ER and PR from a breast carcinoma specimen provide a correct picture of the endocrine characteristics of the tumor independently of the serum concentrations of estradiol, progesterone, FSH, LH and prolactin.