Polymorphisms of COX-2 -765G>C and p53 codon 72 and risks of oral squamous cell carcinoma in a Taiwan population

The association between polymorphisms of COX-2 -765G>C and p53 codon 72, and oral squamous cell carcinoma (OSCC) remains unclear. We investigated the associations between COX-2 and p53 polymorphisms, oral precancerous lesions (OPL), and OSCC. Demographic data and substance use (smoking, drinking, and betel quid chewing) data were collected from 297 patients with OSCC, 70 with oral leukoplakia (OL), 39 with oral submucosal fibrosis (OSF), and 280 healthy controls. COX-2 and p53 polymorphisms were determined by PCR-RFLP methods. A significantly higher proportion of OSCC and OPL patients were male, and frequent habitual users of the three substances. No association was found between p53 and COX-2 polymorphisms, ethnicity, and gender. Polymorphisms of p53 were not associated with OSCC development and malignant potential of OPL, OSF, and OL. The frequency of COX-2 -765G/G genotype was significantly higher in healthy controls (chi(2)=93.83, p<0.0001). After adjusting for possible confounding factors, COX-2 -765C allele vs. -765G/G genotype (OR=0.22, 95%CI=0.12-0.39) was a protective factor against OSCC development, but was a risk factor for malignant potential of OSF (OR=3.20, 95%CI=1.32-8.94) and OL (OR=6.73, 95%CI=2.84-19.87). We suggest that COX-2 -765G>C polymorphisms play a different role in OSCC development than in malignant potential of OSF and OL. However, p53 codon 72 polymorphisms show no such correlation.