Estrogen and progesterone receptors in endometriotic tissue and endometrium: comparison according to localization and recurrence

Abstract

To study the hormonal regulation of primary and recurrent endometriosis by comparing the levels of estrogen receptors (ER) and progesterone receptors (PR) with the levels in uterine endometrium obtained simultaneously. Tissue samples collected at routine operations. One university clinic. A total of 69 endometriotic samples were obtained from 61 women, and endometrium was obtained from 54 of the women. Seventeen of the patients (26%) had a recurrent disease; the others (n = 49) were operated on for the first time. Samples from recurrences constituted 18% (6/34) of the endometriomas, 37% (10/27) of the biopsies from ovarian lesions, and 4 of 5 biopsies from peritoneal endometriosis. In primary endometriotic lesions, both ER and PR were significantly lower than in endometrium. In recurrent lesions, ER levels in cytosol were significantly lower than in endometrium, but there was no difference concerning PR. In endometriotic tissue, the PR level was significantly higher in recurrent than in primary tissue, but there was no difference concerning ER. The ER level was significantly lower in ovarian but not in peritoneal endometriosis, compared with endometrium. No difference was seen concerning PR. This study shows differences in ER and PR levels in primary and recurrent endometriosis and indicates a different hormonal regulation of the two stages of the disease.