Xanthine oxidase in eutopic and ectopic endometrium in endometriosis and adenomyosis

OBJECTIVE: To investigate the expression of xanthine oxidase in eutopic and ectopic endometrium in endometriosis and adenomyosis. DESIGN: Immunohistochemical identification of xanthine oxidase in endometrial tissues by using polyclonal antibody. SETTING: University hospital. PATIENT(S): Thirty-four women with endometriosis, 34 women with adenomyosis, and 44 fertile control women. INTERVENTION(S): Biopsy samples were obtained from the endometrium throughout the menstrual cycle. MAIN OUTCOME MEASURE(S): Semiquantitative immunostaining (evaluation nomogram) score of endometrial cells. RESULT(S): The level of xanthine oxidase expression in the glandular epithelium of control varied according to menstrual phase, but no such variation in expression was seen in endometriosis. Variation in xanthine oxidase expression was observed during the menstrual cycle in patients with adenomyosis; this variation differed completely from that in controls. Xanthine oxidase expression was found in ectopic endometrial tissue in all cases. The mean evaluation nomogram levels in the glandular epithelium in adenomyosis tissue were as high as those in the early secretory phase in the eutopic endometrium. CONCLUSION(S): Aberrant expression of xanthine oxidase in eutopic and ectopic endometrium appears to play a pathologic role in endometriosis and adenomyosis.