Cyclooxygenase-2 expression is higher in ovarian cancer tissue adjacent to endometriosis than in ovarian cancer without comorbid endometriosis.

Objectives: The purpose of this study was to examine if COX-2, CK7 and CK20 are involved in the malignant transformation of endometriosis.

Methods: We compared COX-2, CK7 and CK20 expressions between isolated endometriosis lesions and endometriosis lesions adjacent to ovarian carcinoma and between isolated ovarian carcinoma and ovarian carcinoma with implants of endometriosis. Immunoreactivity was quantified using an immunohistochemical scoring system that corresponds to an image analysis-based system.