Correlation of cyclooxygenase-2 pathway and VEGF expression in head and neck squamous cell carcinoma

The purpose of this study was to determine whether cyclooxygenase-2 (COX-2) was overexpressed in head and neck squamous cell carcinoma (HNSCC) in relation to vascular endothelial growth factor (VEGF) expression and lymph node metastasis. COX-2 has an important role in the promotion of carcinogenesis, tumor invasiveness and angiogenesis. VEGF is a proangiogenic factor that is up-regulated in various tumors. VEGF has been shown to interact with COX-derived prostaglandins in angiogenesis. To better understand the roles of these genes in HNSCC, we evaluated the immunohistochemical expression pattern of COX-2 and VEGF in relationship with histologic differentiation, clinical stage, and nodal status in 146 HNSCC. The COX-2/VEGF double immunofluorescein staining was evaluated with confocal scanning laser microscope. A positive expression was seen in 96% (140/146: 98 strong positive, 42 weakly positive) for COX-2 and in 98% (143/146: 63 strong positive, 80 weakly positive) for VEGF in HNSCC. A correlation was present in the positive expression of COX-2 with histologic differentiation, clinical stage, and nodal status. VEGF expression was also correlated with nodal status. A significant relation was observed between COX-2 and VEGF expressions. The simultaneous expression of COX-2 and VEGF was statistically significant (p<0.05). These results indicate that elevated COX-2 or VEGF expression is more common in HNSCC with poor prognostic characteristics. The present findings support the efforts to initiate clinical trials on the efficacy of COX-2 inhibitors in adjuvant treatment of HNSCC.