We conducted a hospital-based case-control study including 727 cases and 736 healthy controls to evaluate the associations of the polymorphic phase-I and -II biotransformations (CYP1A1, CYP1A2, GSTM1, GSTT1, GSTP1, NAT1 and NAT2) and DNA-repair enzymes (XRCC1, XRCC3 and XPD) with the risk of contracting colorectal cancer.
Our results suggest that the XRCC1Arg399Gln polymorphism may contribute to the risk of early-onset colorectal cancer and the XRCC3 Thr241Met polymorphism may modify the risk for meat-associated colorectal cancer.
The risk for colorectal cancer did not appear to differ significantly amongst individuals featuring the XRCC1 399Arg/Arg genotype (OR = 1.18; 95% CI, 0.96-1.45), the XRCC3 241Thr/Thr genotype (OR = 1.25; 95% CI, 0.88-1.79) or the XPD 751Gln allele (OR = 1.20; 95% CI, 0.90-1.61), although individuals featuring a greater number of risk genotypes (genotype with OR greater than 1) did experience a higher risk for colorectal cancer when compared to those who didn't feature any risk genotypes (Trend test P = 0.03).
Our results suggest that polymorphisms in the XRCC1 genes may contribute to colorectal cancer susceptibility, and some evidence was obtained of a genetic modification for the relationship between alcohol intake and colorectal cancer.
Weak association was found between the XRCC1 Arg/Arg and Gln/Gln variants and the risk of colorectal cancer (OR = 1.28; 95% CI 1.00-1.84 and OR = 1.13; 95% CI 0.85-2.34, respectively).
The data suggest that the polymorphism in exon 10 of the XRCC1 gene may be associated with resistance to oxaliplatin/5-FU chemotherapy in advanced colorectal cancer.
In a pilot case-control study, we tested the hypothesis that polymorphisms in the gene for the DNA repair enzyme XRCC1 are associated with increased risk of colorectal cancer among Egyptians.