["Cyclooxygenase (COX) is the rate-limiting enzyme that catalyzes the conversion of arachidonic acid to prostaglandins. The purpose of the present study was to investigate the involvement of COX-2 protein in breast cancer biological behavior through its correlation with the well-known clinicopathological parameters and the expression of p53, c-erbB-2, topoisomerase IIalpha (topoIIalpha) and peroxisome proliferator-activated receptor (PPARgamma) proteins, as well as its effect on patients' survival.", 'We performed immunohistochemistry to detect COX-2, estrogen receptor (ER), progesterone receptor (PR), p53, c-erbB-2, topoIIalpha and PPARgamma proteins in 175 cases of invasive breast carcinomas. The results were elaborated by statistic analysis.', 'Cytoplasmic expression of COX-2 was detected in 66.9% of breast carcinoma samples and was inversely correlated with both nuclear and histological grade (p < 0.0001 and p = 0.039, respectively), whereas its association with PR was found to be positive (p = 0.016). COX-2 expression was inversely correlated with topoIIalpha and p53 (p = 0.033 and p = 0.002, respectively), whereas its association with PPARgamma was parallel (p < 0.0001). In addition, c-erbB-2 of tumor cells was inversely correlated with COX-2 in stromal cells of the tumor (p = 0.011). Neither univariate nor multivariate analysis demonstrated any association between COX-2 expression and patient overall or disease-free survival.'] Is overexpression of cyclooxygenase-2 associated with a favorable prognostic phenotype in breast carcinoma?