Contribution of DNA Repair Xeroderma Pigmentosum Group D Genotypes to Colorectal Cancer Risk in Taiwan

Abstract

Background/aim: It has been previously proposed that genetic variations on DNA repair genes confer susceptibility to cancer and the DNA repair gene Xeroderma Pigmentosum Group D (XPD) is thought to play the role of a helicase during excision repair and transcription. We investigated three genotypes of XPD, at promoter -114 (rs3810366), Asp312Asn (rs1799793) and Lys751Gln (rs13181), regarding their association with colorectal cancer susceptibility in a Taiwanese population.

Materials and methods: In total, 362 patients with colorectal cancer and 362 gender- and age-matched healthy controls were genotyped by polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP), and their XPD genotypes' association with colorectal cancer risk was investigated.

Results: The genotypes of XPD Asp312Asn (p=0.2493), Lys751Gln (p=0.7547) and promoter -114 (p=0.8702), were not associated with susceptibility for colorectal cancer. The Chi-square test revealed that the variant alleles of XPD Asp312Asn, Lys751Gln and promoter -114 was not associated with susceptibility for colorectal cancer either [p=0.1330, 0.3888 and 0.8740; odds ratio (OR)=1.20, 0.83 and 0.98; 95% confidence interval (95%CI)=0.95-1.52, 0.54-1.27 and 0.80-1.21, respectively]. The risk of A/G and A/A genotypes have no association with cancer risk among non-alcohol drinkers (OR=1.24, 95%, CI=0.90-1.72, p=0.2103) or alcohol drinkers (OR=1.51, 95% CI=0.64-3.55, p=0.4648). There exists no obvious contribution of XPD genotypes to tumor size (p=0.3531), location (p=0.3006) and lymph node metastasis (p=0.1061).

Conclusion: Asp312Asn, Lys751Gln and promoter -114 of the XPD gene were not found to be adequate predictive markers for colorectal cancer risk in Taiwan.

Keywords: Alcohol drinking; XPD; colorectal cancer; genotype; polymorphism.