The Relationship Between Cyclooxygenase-2 Expression and Colorectal Cancer

CONTEXT Epidemiological studies have implicated the inducible form of cyclooxygenase (COX-2) in the pathogenesis of colorectal cancer; however, its role is not fully understood. OBJECTIVE To examine the relationship between the expression of COX-2 in human colorectal cancer and patient survival. DESIGN Patients diagnosed as having colorectal cancer were evaluated and followed up for up to 9.4 years (median follow-up, 2.7 years). Tumor sections were stained for COX-2 using a rabbit polyclonal antibody raised against human COX-2. The extent of COX-2 staining was graded by 2 observers blinded to outcome. Preabsorption of the anti–COX-2 antibody with a COX-2 peptide abolished the staining, demonstrating the specificity of the assay. SETTING Gastrointestinal unit of a large general teaching hospital in Dublin, Ireland. PARTICIPANTS Seventy-six patients (median age, 66.5 years) with colorectal cancer (Dukes tumor stage A, n=9; Dukes B, n=30; Dukes C, n=25; Dukes D, n=12) whose diagnosis was made between 1988 and 1991. Fourteen normal colon biopsies were stained for COX-2 as controls. MAIN OUTCOME MEASURES Survival in years following diagnosis compared by extent of COX-2 epithelial staining (grade 1,