Analysis of cyclooxygenase-2 (COX-2) expression in different sites of endometriosis and correlation with clinicopathological parameters

BACKGROUND: Recent studies have demonstrated the overexpression of cyclooxygenase-2 (COX-2) in endometriosis. The aim of this study was to investigate the expression of COX-2 in different anatomical sites of endometriosis and its association with clinico-pathological parameters in a single institutional series of patients undergoing operative treatment. METHODS: COX-2 expression was analysed by immunohistochemistry in 136 samples of endometriotic tissue from 103 patients affected by endometriosis. RESULTS: COX-2 immunoreaction was observed in 78.5% of ovarian endometriotic cysts, in 11.1% of peritoneal implants and 13.3% of recto-vaginal nodules. COX-2 positivity was not distributed differently according to age, pre-operative serum levels of CA125 and AFS score. Moreover, COX-2 positivity did not show any significant variation according to the subjective intensity of pain, as dysmenorrhoea, chronic pelvic pain, lower urinary tract or gastrointestinal symptoms, or according to infertility. CONCLUSIONS: Increased COX-2 expression in the endometriotic ovarian cyst wall was observed with respect to other extraovarian localizations. No relevant correlations between COX-2 positivity and clinico-pathological characteristics and symptoms of patients were observed.