Association between DNA double strand break gene Ku80 polymorphisms and oral cancer susceptibility

The DNA double strand break repair gene Ku80 is thought to play a major role in the caretaking of the overall genome stability. It is very possible that defective in double strand break repair capacity can lead to human carcinogenesis. Thus, the polymorphic variants of Ku80 were firstly investigated regarding their association with oral cancer susceptibility. In this hospital-based case-control study, the association of Ku80 promoter G-1401T (rs828907), promoter C-319T (rs11685387), and intron19 (rs9288518) polymorphisms with oral cancer risk in a Taiwanese population was investigated. 600 patients with oral cancer and 600 age- and gender-matched healthy controls recruited were genotyped and analyzed by PCR-RFLP method. There were significant differences between oral cancer and control groups in the distributions of their genotypes (P=0.0038) and allelic frequencies (P=0.0044) in the Ku80 promoter G-1401T polymorphism. In the other two polymorphisms, there was no difference between both groups in the distribution of either genotype or allelic frequency. There is a synergistic gene-environmental interaction between Ku80 and areca chewing. Compared with G/G genotype in Ku80 promoter G-1401T, the G/T plus T/T significantly enhanced the risk only in the areca chewers (odds ratio=1.603; 95% confidence interval=1.053-2.011), not in the non-areca chewers. In conclusion, the Ku80 promoter G-1401T is correlated with oral cancer susceptibility and this polymorphism may be a useful marker for oral cancer prevention and early detection.