Comprehensive pathway-based interrogation of genetic variations in the nucleotide excision DNA repair pathway and risk of bladder cancer.

BACKGROUND

Growing evidence suggests that single nucleotide polymorphisms (SNPs) in nucleotide excision repair (NER) pathway genes play an important role in bladder cancer etiology. However, only a limited number of genes and variations in this pathway have been evaluated to date.

METHODS

In this study, the authors applied a comprehensive pathway-based approach to assess the effects of 207 tagging and potentially functional SNPs in 26 NER genes on bladder cancer risk using a large case-control study that included 803 bladder cancer cases and 803 controls.

RESULTS

In total, 17 SNPs were associated significantly with altered bladder cancer risk (P < .05), of which, 7 SNPs retained noteworthiness after they were assessed with a Bayesian approach for the probability of false discovery. The most noteworthy SNP was reference SNP 11132186 (rs11132186) in the inhibitor of growth family, member 2 (ING2) gene. Compared with the major allele-containing genotypes, the odds ratio was 0.52 (95% confidence interval, 0.32-0.83; P = .005) for the homozygous variant genotype. Three additional ING2 variants also exhibited significant associations with bladder cancer risk. Significant gene-smoking interactions were observed for 3 of the top 17 SNPs. Furthermore, through an exploratory classification and regression tree (CART) analysis, potential gene-gene interactions were identified.

CONCLUSIONS

In this a large association study of the NER pathway and the risk of bladder cancer, several novel predisposition variants were identified along with potential gene-gene and gene-environment interactions in modulating bladder cancer risk. The results reinforce the importance of a comprehensive, pathway-focused, and tagging SNP-based candidate gene approach to identify low-penetrance cancer susceptibility loci.