Background & objective: Recently, it has been recognized that both cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) produce important endogenous factors of human tumor progression. However, the biological significance of the adnormal expression of COX-2 and iNOS in tongue squamous cell carcinoma remains unclear. This study was to investigate the expression of COX-2 and iNOS in tongue squamous cell carcinoma and precancerous lesions, and analyze their interrelation.
Methods: The expression of COX-2 and iNOS in 59 specimens of tongue squamous cell carcinoma (SCC), 45 specimens of hyperplasia (22 cases of mild hyperplasia, 20 cases of moderate hyperplasia, and 3 cases of severe hyperplasia), and 36 specimens of pericancerous normal epithelium was detected by SP immunohistochemistry.
Results: The positive rates of COX-2 were 8.3% in normal epithelium, 4.5% in mild hyperplasia, 5.0% in moderate hyperplasia, 0 in severe hyperplasia, and 45.8% in SCC, respectively; those of iNOS were 44.4% in normal epithelium, 72.7% in mild hyperplasia, 80.0% in moderate hyperplasia, 100% in severe hyperplasia, and 98.3% in SCC, respectively. The positive rates of COX-2 and iNOS were significantly higher in SCC than in normal epithelium (P < 0.001); the positive rate of iNOS was also significantly higher in hyperplasia than in normal epithelium (P < 0.001). The overexpression of COX-2 and iNOS was positively correlated with pathologic grade of the lesions (r = 0.418, P < 0.001; r = 0.607, P < 0.001). COX-2 expression was positively correlated with iNOS expression (r = 0.245, P < 0.001). CONCLUSOIN: The overexpression of COX-2 and iNOS is closely related to the carcinogenesis of the tongue.