Cyclooxygenase-2 is over-expressed in Chinese esophageal squamous cell carcinoma, and correlated with NF-kappaB: an immunohistochemical study

BACKGROUND: Cyclooxygenase-2 (COX-2), the inducible isoform of the key enzyme in the synthesis of prostaglandins, has been found to be over-expressed in several human cancers. The aim of the present study was to investigate immunohistochemical expression of COX-2 in esophageal squamous cell carcinoma (SCC) and relationship with clinicopathological parameters and NF-kappaB. METHODS: Expression of COX-2 and NF-kappaB was investigated in 69 cases of esophageal SCC by immunohistochemistry and the correlation of COX-2 expression with clinicopathological features and NF-kappaB staining was examined. RESULTS: Thirty-one esophageal SCC (31/69, 44.9%) had positive expression of COX-2. COX-2 was expressed significantly higher in well-differentiated tumors (16/23, 69.6%) than that in moderate (13/34, 38.2%) and poor (2/12, 16.7%) differentiation (P = 0.034). COX-2 expression was increasingly progressive with the advance of the clinical stages significantly (P = 0.045). The correlation between COX-2 (47/99, 47.5%) and NF-kappaB/p50 (54/99, 54.5%) immunostaining was statistically significant (P = 0.030). CONCLUSIONS: COX-2 is over-expressed in esophageal SCC, especially in a well differentiation, correlated with tumor progression, and possibly regulated by NF-kappaB.