The Expression Of COX-2,ER And PR In The Endometrial Polyps In Postmenopausal Women And Their Clinical Significance

ObjectiveEndometrial polyp, one of the most frequent gynaecological diseases that affects women, usually causes abnormal uterine bleeding, endometrial thickness and infertility. Asymptomatic endometrial polyps can be detected accidentaly.Recently,the incidence rate of endometrial polyps has been increasing by the spread use of transvaginal sonography, sonohysterography and hysterscopy . Although endometrial polyp is a benign disorder, occasionally, a focus of recidivation and malignancy may be found in postmenopause women whose incidence rate and malignant potential are higher than those in pre-menopause women. These affected women suffer a lot . The pathogenesis of endometrial polyps has been poorly understood up to now.Therefore, it is difficult to be completely cured. There are some kinds of hypothesis about endometrial polyps. Traditionally,it relates to inflammation and can be considered a kind of reactive hyperplasia which results from long-term and repeated mechanical stimulations and undergos biologic inflammatory factors in endometrium. It can also be thought that endometrial polyps are benign tumors of endometrium. Some scholars suspect that it is a kind of signal of precancerosis similar to proctopolypus. At present, the majority consider that the pathogenesis of endometrial polyps is related to endocrine disturbance in premenopause women. The reasons for the higher incidence rate of EP in postmenopause women were presumed that it is related to poor endometrium which is easy to be infected or related to the continual stimulation of estrogen. The estrogen binding estrogen receptor can promote the growth of endometrium. Reversely, the progestogen binding progestogen receptor has the restraining effect to the growth of endometrium. Hormones present its physiological effect by binding its receptors. Therefore, the change of specific hormone receptors in endometrial cells would regulate the action of hormones. Cyclooxygenase-2(COX-2) is the rate-limiting enzyme , which has two functions: cycloxygenase and peroxidase, and catalyzes the conversion of arachidonic acid to prostaglandins. Then, the strong biological effect resulting from PGs would present in the local lesions.It may also play a role in stimulation of cell growth, suppression of apoptosis, promotion of angiogenesis, and immune suppression. At present, many researches on COX-2 focus on tumors.There have a few reports on the endometrial polyp at home. The aim of the study is to detect COX-2,ER,PR protein expression in endometrial polyp tissues and endometrium from women with and without endometrial polyps,to analyse their expression difference and to investigate the change of endometrial tissues so that we will provide theoretic basis for aetiology and mechanism of endometrial polyps and find a new method for its effective remedy .MethodsImmunohistochemical method was used to detect the expressions of ER,PR and COX-2 protein in 35 cases of endometrial polyps(polyps), 35 cases of endometrium with endometrial polyps(patients' endometrium) and 16 cases of endometrium without endometrial polyps(control endometrium) in postmenopausal women. It was evaluated by way of semiquantitative analysis. SPSS 13.0 is performed to analyze the study data. Statistical significance was defined as P < 0.05.Results1) COX-2 protein mainly localized in cytoplasm was expressed in gland epithelial cells of control endometrium, of patients' endometrium and of polyps.2) ER,PR proteins mainly localized in nucleolus were expressed in gland epithelial and stromal cells of control endometrium. of patients' endometrium and of polyps.They were also detected positively in part in vascular endothelial cells.3) COX-2 protein was significantly higher in both glands and stroma of polyps than in patients' endometrium and control endometrium (P < 0.05).4) The expressions of PR protein was significantly lower in both glands and stroma of polyps than in patients' endometrium and control endometrium (P < 0.05).5) The expressions of COX-2,ER and PR protein were of no significant difference between patients' endometrium and control endometrium( P>0.05).Conclusions1) COX-2 protein was significantly higher in polyps than in patients'endometrium and control endometrium in both glands and stroma. The up-regulated COX-2 may promote releasing of PGs, stimulate cell growth and promote angiogenesis in local tissues. Probably it plays a key role in promoting the growth of polyps.2) The expression of ER protein was of no significance in all groups, and the expression of PR protein was significantly lower in polyps than in patients' endometrium and control endometrium in both glands and stroma. It was supposed that polyp tissues from postmenopausal women react to estrogen, and become insensitive to progestogen which restrains the endometrial hyperplasia. So polyps probably result from continuous stimulus of estrogen, from lack of inhabitation of progestogen and from local over hyperplasia .3) The expressions of COX-2,ER and PR protein were of no significant difference between endometrium and control endometrium. It indicates that the endometrium from postmenopausal women with polyps is similar to the endometrium from normal postmenopausal women.It can be concluded that endometrial polyp is a kind of focal disease.The aim of treatment can be reached by local treatment.4) The COX-2,ER and PR proteins play an important role in the development of endometrial polyps. Therefore, only drugs can control the development of endometrial polyps and gain the aim of radical cure in molecular level. It will open a new way to cure endometrial polyps in the near future, if an effective medical treatment is devised, developed and applied to clinical therapy.