Studies on the Contribution of Cox-2 Expression in the Progression of Oral Squamous Cell Carcinoma and H-Ras Activation.

Abstract

The aim of this study was to investigate the relationship between the H-ras and Cox-2 gene expression in tumors from Iranian Oral Squamous Cell Carcinoma (OSCC) patients. Fresh tumor biopsies removed from oral cavity were collected from 67 new cases. Total RNA was extracted from biopsies and processed for quantification of H-ras and Cox-2 specific RNA expression using real-time PCR (QPCR). In addition, 59 gingival biopsies from apparently normal individuals were processed for QPCR assays. The results showed that Cox-2 expression at mRNA levels was at minimal levels in normal gingival biopsies. However, there was a surge in Cox-2 expression in tumor tissues (11.5 fold, p<0.0001). Cox-2 expression was elevated depending on the tumor grade and there was a 1.7 fold increase (p=0.003) in tumors diagnosed as MD/PD compared to that pathologically diagnosed as WD. This inflammatory marker was increased more significantly in smoker patients compared to non-smoker matching group. The H-ras expression at mRNA levels was significantly higher in OSCC samples compared to normal gingival (3 fold; p=0.044). This expression was significantly higher in tumors diagnosed as MD/PD compared to WD (1.59 fold, p=0.033). In conclusion, we found a correlation between H-ras expression and Cox-2 induction in OSCC tissue, suggesting that together these genes are contributing to cancer progression. Cox-2 is an early event in cancers of mucosal epithelial cells and a surge in Cox-2 expression in OSCC could be partly due to pro-inflammatory factors such as smoking.