We detected the distributions of three single-nucleotide polymorphisms (XRCC1 Arg399Gln, XRCC3 Thr241Met and XPD Lys751Gln) in DNA repair genes, and assessed the associations of these genetic polymorphisms with colon and rectal cancer susceptibility as well as evaluated the interactions of gene-gene and gene-environment in a case-control study of an Indian population.
We genotyped 1,181 controls and 311 cases (180 colon and 131 rectal cancer) for SNPs in the XRCC1 (Arg194Trp, Arg399Gln), OGG1 (Ser326Cys), PARP (Val762Ala, Lys940Arg), and XPD (Asp312Asn, Lys751Gln) genes.
These interactions were stronger for rectal cancer cases (heterogeneity test P = 0.002 for XPD Asp312Asn and P = 0.03 for XPD Lys751Gln) and remained statistically significant after accounting for multiple testing.