[Study on the relationship between estrogen receptor beta and etiology of human endometrial polyps]

To investigate the relationships between the expression of estrogen receptor beta (ERbeta) and etiology of human endometrial polyps (EP).

Thirty-six females with infertility and 36 females with intrauterine contraceptive device (IUD, aged from 23 years to 33 years, average 28 years) were enrolled in the study. Blood samples were taken before hysteroscopy for analysis of the level of estradiol in serum. All the tissue samples of benign EP and endometrium in the same cycle were obtained through hysteroscopy on the 5th to 9th days of menstruation cycle (all the women selected had the same menstrual period). Part of the samples of EP were made into homogenates to assay the level of estradiol, and the rest of EP and endometrium were both fixed with 10% formalin. If one of the samples was confirmed by histopathologic analysis, the correspondence was eligible. Otherwise, they were abnegated. Seventy-two samples were collected and 60 were eligible as a result. The expression of ERbeta and ERalpha in these samples was detected by immunohistochemical staining, while the levels of estradiol in both serum and homogenate of EP were detected by radioimmunoassay.

The expression of stromal ERbeta of EP in infertility and IUD groups (2.1 +/- 0.9, 1.9 +/- 0.5) was significantly higher than those of endometrium in the same cycle (1.7 +/- 0.3, 1.3 +/- 1.1) (P < 0.05), while the expression of stromal ERalpha of EP was significantly decreased than those of endometrium (P > 0.05). The expression of ERbeta in glands had no difference in both EP and endometrium. The expression of ERbeta was significantly positively related to the levels of estradiol in both serum and homogenate (P < 0.01), while the expression of ERalpha had no correlation with estradiol.

Overexpression of ERbeta in stroma might play an important role in the pathogenesis of EP.