Clinicopathologic significance of expression of cyclooxygenase-2 in human esophageal squamous cell carcinoma

BACKGROUND/AIMS: The focus of studies on cyclooxygenase-2 (COX2) 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 COX2 in esophageal squamous cell carcinoma. METHODOLOGY: The immunohistochemical expression of COX2 was examined for 68 specimens of esophageal squamous cell carcinoma (ESCC) and the correlation of COX2 expression with clinicopathologic features was examined. COX2 immunoreactivity was weak in 27 (40%) and strong in 41 (60%) of the carcinomas. RESULTS: The proportion of poorly differentiated SCCs among tumors with a strong expression of COX2 (34%, 14 of 41) was significantly higher than among tumors with a weak expression of COX2 (19%, 3 of 14, p = 0.02). The depth of the tumors (p = 0.0004), lymph node metastasis (p = 0.009) and the stage of the tumors (p = 0.001) were advanced significantly more progressively in ESCCs with a strong COX2 expression. Moreover, survival was significantly reduced (p = 0.02) among patients with strong COX2 expression when compared with the COX2 weak group. CONCLUSIONS: This study showed that strong expression of COX2 was correlated with tumor progression and poor differentiation in ESCC.