What is the influence of cyclooxygenase-2 on postmenopausal endometrial polyps?

BACKGROUND: The genesis of the endometrial polyp is as yet unclear. There is evidence that the polyp is related to the inflammatory process and that it interacts with the cyclooxygenase-2 (COX-2) enzyme. OBJECTIVE: To review the influence of COX-2 on the postmenopausal endometrial polyp. METHODS: A systematic review was made of the Medline, Embase, and Cochrane databases, covering the years of 2001-2014. The inclusion criteria were: experimental studies with immunohistological analysis of COX-2 in endometrial polyps; women; hysteroscopic and surgical evaluation; and studies with comparisons between the endometrial polyp and other tissues (normal endometrium, adjacent endometrium, and other uterine diseases). The exclusion criteria were: polyps in other organs; genetic polymorphisms; endometrial cancer exclusively; abnormal uterine bleeding unrelated to polyps. The search key words (taken from the Medical Subject Headings - MeSH) were endometrial polyp and cyclooxygenase-2. RESULTS: Seven of ten articles were selected. Results showed positive COX-2 expression in the glandular epithelium of the polyps, and expression was more intense when the polyp was malignant. However, there was a study which did not find any difference between polyps and the normal endometrium, and there was another which compared polyps in menacme with postmenopausal polyps. CONCLUSION: There is no consensus in the literature as to the participation of COX-2 in the development of benign and/or malignant endometrial polyps. In all of the studies, COX-2 was present in the postmenopausal polyps and with greater intensity in the malignant ones.