Correlation of cyclooxygenase-2 (COX-2) and aromatase expression in human endometrial cancer: tissue microarray analysis.

Objective: The objective of this study was to compare the prevalence of cyclooxygenase-2 (COX-2), aromatase, and hormone receptor immunohistochemical (IHC) expression to well defined clinical-pathologic prognostic factors in a large group of surgically staged endometrial cancer patients.
Study Design: A tissue microarray (TMA) was constructed from 336 separate specimens of endometrial cancer. IHC was performed for estrogen (ER) and progesterone (PR) receptor, COX-2, COX-1, and aromatase.
Results: The majority of tumors expressed COX-2 (59%) and aromatase (65%). COX-2 staining significantly correlated with aromatase expression ( P < .014) but did not correlate with ER and PR. COX-2 expression was correlated with worsening histologic grade ( P < .026) and approached statistical significance for deep myometrial invasion ( P < .055). After applying multivariate analysis, no single IHC or combination of IHCs correlated with intrauterine poor prognostic factors or advanced stage. Only myometrial invasion >50% (OR 6.98, P < .001) and nonendometrioid histology (OR 4.933, P < .001) were predictive of advanced stage after multivariate analysis.
Conclusion: COX-2 and aromatase are expressed in the majority of endometrial cancer patients. COX-2 expression was not associated with the great majority of surgical-pathologic prognostic factors. COX-2 expression did significantly correlate with aromatase expression, suggesting that intratumoral production of estrogen in endometrial cancer may be an important mechanism in tumorigenesis.