Aspirin and the Risk of Colorectal Cancer in Relation to the Expression of COX-2

摘要: BACKGROUND Regular use of aspirin reduces the risk a colorectal neoplasm, but mechanism by which affects carcinogenesis in colon is not well understood. METHODS We estimated cyclooxygenase-2 (COX-2) expression immunohistochemical assay sections from paraffin-embedded colorectal-cancer specimens two large cohorts participants who provided data on questionnaire every 2 years. applied Cox regression to competing-risks analysis compare effects relative cancer relation COX-2 tumor. RESULTS During 2,446,431 person-years follow-up 82,911 women and 47,363 men, we found 636 incident cancers that were accessible for determination expression. Of tumors, 423 (67%) had moderate or strong The effect differed significantly (P heterogeneity=0.02). conferred significant reduction overexpressed (multivariate risk, 0.64; 95% confidence interval [CI], 0.52 0.78), whereas regular no influence tumors with weak absent 0.96; CI, 0.73 1.26). age-standardized incidence rate was 37 per 100,000 among users, as compared 56 those did regularly; contrast, 27 28 nonregular users. CONCLUSIONS appears reduce overexpress COX-2.