[Expressions of aromatase P450 and estrogen receptor in eutopic and ectopic endometrium in endometriosis and their correlation with endometriosis].

OBJECTIVE: To detect the expression of aromatase P450 and estrogen receptor (ER) in eutopic and ectopic endometrium in endometriosis and their correlation with endometriosis.

METHODS: Forty patients who had undergone operation because of endometriosis (all were stage III-IV according to the revised American Fertility Society classification) were enrolled and 83 tissue specimens from different locations of disease foci were obtained and divided into five groups according to the location: group I, eutopic endometrium of 25 cases; Group II, ovarian endometriosis tissues of 23 cases; Group III, vagina-rectum endometriosis tissues of 11 cases; Group IV, peritoneum endometriosis tissues of eight cases; and group V, uterine serosa endometriosis tissues of 16 cases. Control group consisted of normal endometrium taken from 20 fertile women who had endometrial curettage before placement of intrauterine device. The routine two-step immunohistochemical technique was used to measure the expression of aromatase P450 and ER in endometrial cells.

RESULTS: Expressions of aromatase P450 and ER in group I [histochemistry score (H-score), 2.6 +/- 1.0, 3.8 +/- 0.5] were significantly higher than those in control group (both P < 0.01), group II (1.4 +/- 1.0, 1.9 +/- 1.6) (P < 0.05, P < 0.01), and group III (1.2 +/- 0.9, 1.8 +/- 1.6) (both P < 0.05). Expressions of aromatase P450 and ER had positive correlation in all groups (r = 0.577, P < 0.01).

CONCLUSIONS: Aromatase P450 could increase estrogen and estrogen receptor levels in the local ectopic tissues, thus promoting the growth and implantation of endometriosis. Different types of endometriosis focus have different levels of hormone regulation.