Cyclooxygenase-2 expression is related to prognosis in patients with esophageal squamous cell carcinoma

Esophageal carcinoma is one of the most aggressive malignancies. Many studies have examined various biological factors associated with the malignant potential of esophageal carcinoma. Cyclooxygenase (COX)-2 is overexpressed in various types of human malignancies, including esophageal carcinomas. Although some groups have described COX-2 expression in esophageal adenocarcinoma, few studies have reported COX-2 expression in esophageal squamous cell carcinoma (ESCC).

We immunohistochemically investigated relationships between COX-2 overexpression in surgical specimens of primary tumors in 228 patients with ESCC. Relationships between COX-2 expression and clinicopathological factors, including prognosis, were analyzed. COX-2 expressions were classified into 4 criteria: Score 0, no staining; Score 1, <10% staining; Score 2, 10-90% staining; and Score 3, >90% staining.

Scores of COX-2 immunoreactivity in 228 patients were as follows: Score 0, 21 of 228; Score 1, 71of 228; Score 2, 117 of 228; and Score 3, 19 of 228, respectively. COX-2 expression was significantly correlated with depth of invasion and tumor stage (p=0.03 and p=0.04, respectively). The 5-year survival rate of patients decreased significantly with increased expression of COX-2 (p=0.005). Multivariate regression analysis indicated COX-2 expression as an independent prognostic factor for ESCC.

COX-2 overexpression was significantly correlated with depth of invasion, tumor stage and survival in ESCC. Evaluation of COX-2 expression should be useful for determining tumor properties, including prognosis, in patients with ESCC.