Alteration of the risk of oral pre-cancer and cancer in North Indian population by XPC polymorphism genotypes and haplotypes

Chewing and smoking of tobacco have been reported to cause DNA damage in oral mucosa which can be repaired by Xeroderma Pigmentosum Group C (XPC) protein. This study aimed to evaluate the association of XPC gene polymorphisms with the risk of oral diseases including oral pre cancer and cancer. In the present study we genotyped 302 patients with oral diseases and 300 healthy controls for XPC PAT (D > I), C > T and A > C polymorphisms with PCR-RFLP and PCR method. Haplotypes were constituted from different XPC genotypes with SNPstats programme. Our results show that individuals with D/I genotype for XPC D > I polymorphism were significantly protected from developing Oral submucous fibrosis (OSMF) and Leukoplakia (p = .029 and 0.031 and respectively). Risk of oral cancer was also significantly lower with the I/I genotype of the same XPC polymorphism (p = .048). However, once oral cancer is established, individual with I allele were at significantly increased risk for having high stage and metastatic tumor (p = .011 and 0.03 respectively). Carrier of T allele for XPC C > T polymorphism were significantly protected from development of OSMF (p = .004) but did not show any association with the development of other pre oral cancerous lesions or oral cancer. In contrast, CC genotype as well as C allele for XPC A > C polymorphism was significantly associated with increased risk of Lichenplanus (p = .006 and 0.004 respectively). XPC C > T and A > C polymorphisms did not show any association with clinical parameters of oral cancer. Haplotype D/T/A and I/T/A showed protective association with development of oral disease (P-value = .001 and 0.0001 respectively). In conclusion, results from the present study demonstrate association of XPC polymorphisms with oral pre cancer and cancer.