Significance of immunohistochemical expression of cyclooxygenase-2 in squamous cell carcinoma of the esophagus

Background: The focus of studies on cyclooxygenase-2 (COX-2) have been on its ability to mediate the biological behavior of human tumors including tumorigenesis, tumor progression, apoptosis, and differentiation. The aim of the current study was to elucidate a further finding on the clinicopathologic significance of immunohistochemical expression of COX-2 in esophageal squamous cell carcinoma (ESCC). Methods: The immunohistochemical expression of COX-2 was examined for 76 specimens of ESCC and the correlation of COX-2 expression with clinicopathologic features was examined. Results: Twenty-eight ESCCs (36.8 %) had a strong expression of COX-2. The proportion of poorly differentiated SCCs among tumors with a strong expression of COX-2 (42.8 %, 12 of 28) was significantly higher than that among tumors with a weak expression of COX-2 (16.7 %, 8 of 48; P = .037). The depth of the tumors (P = .003) and the stage of the tumors (P = .015) were advanced significantly more progressively in ESCCs with a strong COX-2 expression. Univariate analysis showed that the prognosis of patients with ESCCs with a strong COX-2 expression was significantly poorer than that of patients with ESCCs with a weak COX-2 expression (P = .017). Multivariate analysis showed that only such tumor-related factors as lymphatic invasion (P = .004), venous invasion (P = .003), and stage of the tumors (P = .021) were found to be associated independently with worse prognosis of the patients with ESCC. Conclusions: Strong expression of COX-2 is correlated with tumor progression and poor differentiation in ESCC. (C) 2005 Excerpta Medica Inc. All rights reserved.