Objective: We aimed to investigate the associations of cyclooxygenase-2 (COX-2) with pathological features and survival in patients with colorectal cancer.
Methods: The expression of COX-2 was examined by immunohistochemistry in 112 primary colorectal cancers, with 64 samples from the corresponding normal mucosa and 16 metastases in the regional lymph nodes of patients with colorectal cancer. The associations of COX-2 expression with clinicopathological features, including survival, were analyzed.
Results: The frequency and intensity of COX-2 staining were remarkably increased from the normal samples (17%) to the primary tumors (72%) and to the metastases (100%). Expressions of COX-2 were 25%, 74%, 78%, and 67% in Dukes' A, B, C, and D tumors, respectively (p = 0.005), and positively related to proliferative activity (p = 0.003). COX-2 expressions were 80% in colonic tumors and 60% in rectal tumors (p = 0.03). The expression of COX-2 was positively related to the better differentiated tumors in the colon (p = 0.04). We were unable to find any relationship of COX-2 with patient age, sex, tumor growth pattern, apoptosis, and patient survival (p > 0.05).
Conclusion: We found that the expression of COX-2 was upregulated from normal cells to primary tumors and to metastases, and related to proliferative activity, tumor location, Dukes' stage, and differentiation. These results further support the evidence that COX-2 may be involved in tumorigenesis and development of colorectal cancer.