[Expression of COX-2 protein in colorectal carcinoma and the clinical implication].

Objective: To investigate the relationship between COX-2 expression and the clinicopathological factors in colorectal carcinoma and assess the prognostic value of COX-2 detection.

Methods: Tissue microarray and immunohistochemistry by SABC method was employed for detecting COX-2 expression in 126 patients with advanced colorectal cancer, and the relationship of COX-2 expression with the clinicopathological features and prognosis of the patients was retrospectively analyzed.

Results: The patients were divided into two groups of low and high COX-2 groups according to the grade and extent of COX-2 expression. High COX-2 expression was detected in 32 (25.4%) cases, and low expression in 94 (74.6%) cases. No significant correlation was noted between COX-2 expression and the patients' age, sex, tumor size, tumor location, histological type, lymphatic-node metastasis and Dukes' classification, but high COX-2 expression was strongly correlated with tumor recurrence and especially with blood-borne metastasis (P<0.05). The survival rate without tumor recurrence for high- and low-COX-2 groups was assessed by the Kaplan-Meier method and compared by log-rank test, which revealed significant difference between the two groups (P=0.0067). Multivariate analysis for all patients suggested that among the 8 prognostic factors (age, sex, tumor size, tumor location, histological type, lymphatic-node metastasis, Dukes' stage, and COX-2 expression), Dukes' stage and COX-2 expression was the independent significant factor related to disease-free survival.

Conclusion: The expression of COX-2 is strongly correlated with recurrence of colorectal cancer, especially with blood-borne metastasis. COX-2 is an independent factor for prognostic evaluation of the patients, and tissue microarray allows rapid, convenient, economic and accurate COX-2 detection for large-scale application.