Cyclooxygenase-2 (COX-2) up-regulation is a prognostic marker for poor clinical outcome of upper tract urothelial cancer

Background: There are no reliable biomarkers for diagnosis, prediction of outcome or treatment effect monitoring for upper tract urothelial carcinoma (UTUC), which is a uniquely prevalent cancer in Taiwan. In the present study, 128 primary UTUC specimens of various grades and primary tumor status were examined for the expression of cyclooxygenase-2 (COX-2) in tumor and stroma tissues aiming to clarify the association of COX-2 expression with clinical outcomes in Taiwanese patients with UTUC. Materials and Methods: Immunohistochemistry was implemented to investigate COX-2 expression levels in 128 paired tumor and stroma specimens. The association of COX-2 expression with tumor progression and prognosis was analyzed. Results: Our data demonstrated that positive COX-2 expression was more frequent in stromal cells (57.0%), than in tumor sites (53.1%), and the up-regulation of COX-2 was strongly associated with higher cancer-specific death and cancer recurrence rates. In COX-2-negative cases, no similar correlation was found. Conclusion: COX-2 expression was up-regulated in both stromal and tumor cells of more than half of the studied UTUC patients and the positive expression of COX-2 in stromal cells may be a potential predictive and prognostic biomarker for UTUC, especially for cancer-specific death and recurrence.