XRCC1 A > G polymorphism, smoking and the risk of squamous cell carcinoma of the head and neck

Background: The XRCC1 gene functions in single strand break and base excision repair (BER) processes. The process of recognizing and excising the modified base in BER is started by OGG1 protein. Objective: The present study aimed to investigate the association of XRCC1, OGG1 polymorphisms with the risk of Squamous Cell Carcinoma of the Head and Neck in north Indian population. Methods: The genotype analysis of XRCC1 (A > G), OGG1 (C > G) polymorphisms for 186 patients of SCCHN, 188 controls subjects been carried out with PCR-RFLP method. Patients were followed up for 5 years, at the end follow up data on survival was available for 81 patients. Risks of SCCHN with the genotypes were estimated with odds ratio. Kaplan-Meier method was used to associate genotypes, survival of SCCHN patients. Results: Smokers with AG genotype of XRCC1 A > G were significantly at lower risk for SCCHN (p value = 0.015, OR = 0.186, 95% CI = 0.05-0.65). In patients with SCCHN the G allele of XRCC1 A > G polymorphism found to significantly increase the risk of lymph node metastasis by 2 folds (p value = 0.039, OR = 2.06, 95% CI = 1.08-3.94). Similarly, G allele of OGG1 C > G polymorphism also found to increase the risk of lymph node involvement in SCCHN patients (p value = 0.06, OR = 0.54, 95% CI = 0.30-0.98). Compared to the patients carrying AA genotype for studied XRCC1 polymorphism individual with variant allele genotypes (AG + GG) had poor cumulative/overall survival and the difference in survival were statically significant (AA vs AG + GG: p value 0.05). Conclusions: Our results indicate a possible association of XRCC1 and OGG1 polymorphisms with the risk and clinical outcome of SCCHN.