Possible role of cyclooxygenase-2 in schistosomal and non-schistosomal-associated bladder cancer.

background and purposeCyclooxygenase (COX) is an angiogenic factor that is strongly related to inflammatory diseases and the development of cancer and metastasis in several cancers. It is overexpressed in a variety of premalignant and malignant conditions, including urinary bladder cancer. Our aim was to investigate and compare the expression of COX-2 enzyme in patients with bladder cancer, chronic cystitis, and normal bladder tissue. The results were correlated to the classic prognostic factors, mainly tumor stage and grade, in a trial to determine the prognostic significance of COX-2 marker. MATERIALS AND

methodsSeventy-five bladder samples were taken, including 50 cases with bladder cancer (31 were schistosomal-associated and 19 non-schistosomal-associated), 20 samples from cases with chronic cystitis (7 were nonschistosomal and 13 were schistosomal cystitis), and 5 samples from normal bladder tissue taken as control. The specimens were stained by streptavidin-biotin immunohistochemistry protocol, with COX-2 monoclonal antibody.

resultsAlthough no notable expression of COX-2 was observed in the normal bladder, it was slightly expressed in chronic cystitis especially in areas of dysplasia and squamous metaplasia, whereas there was a significant increase in COX-2 (P < .001) with moderate-to-strong granular cytoplasmic expression in all malignant histologic types. The COX-2 reactivity was higher in transitional cell carcinoma (TCC) than in squamous cell carcinoma (SqCC) (P < .01). COX-2 expression was significantly higher in schistosomal-associated TCC than in non-schistosomal-associated TCC (P < .01). There was a statistically significant positive correlation between COX-2 expression and tumor grade (P = .0052). COX-2 expression was significantly higher in grade 3 bladder TCC than in grades 1 and 2 bladder TCC (P < .05, P < .01). A correlation between COX-2 expression and progression of bladder TCC also was observed (P = .001). There was a significant difference in COX-2 expression level between the bladder TCCs at different clinical stages (P < .01).

conclusionCOX-2 is overexpressed in schistosomal-associated bladder cancer. COX-2 may be of significance to the development and proliferation of bladder TCC, consistent with a potential role for COX-2 inhibitors in the prevention and management of this disease.