Lack of association between XPG Asp1104His and XPF Arg415Gln polymorphism and breast cancer risk: a meta-analysis of case-control studies

The xeroderma pigmentosum group G (XPG or ERCC5) and group F (XPF or ERCC4) play an important role in DNA repair, and produce dual incision 3' and 5' to the damaged nucleotide fragment. Several polymorphisms in the XPF and XPG gene have been described, including the commonly occurring Asp1104His in XPG and Arg415Gln in XPF. The published data on the association between these polymorphisms and breast cancer remained controversial. This meta-analysis of literatures was performed to derive a more precise estimation of the relationship. A total of 17 studies were identified to the meta-analysis, including 5,235 cases and 5,685 controls for XPG Asp1104His (from ten studies) and 3,910 cases and 3,985 controls for XPF Arg415Gln (from seven studies). Overall, no significantly elevated breast cancer risk was found in all genetic models when all studies were pooled into the meta-analysis (for XPG Asp1104His Asp/His vs. Asp/Asp: OR 1.02, 95% CI 0.94-1.11; His/His vs. Asp/Asp: OR 0.96, 95% CI 0.83-1.11; dominant model: OR 1.01, 95% CI 0.94-1.09; and for XPF Arg415Gln Arg/Gln vs. Arg/Arg: OR 1.00, 95% CI 0.89-1.12; Gln/Gln vs. Arg/Arg: OR 2.40, 95% CI 0.62-9.22; dominant model: OR 1.03, 95% CI 0.90-1.18). In stratified analyses, we observed an overall OR of 5.20 (95% CI 2.08-12.95) for breast cancer developing risk in the Caucasian ethnicity, comparing Gln/Gln type to wild-type Arg/Arg for Arg415Gln polymorphism. In conclusion, this meta-analysis suggests that XPG Asp1104His polymorphism is not associated with increased breast cancer risk, and XPF Arg415Gln may be a low-penetrant risk factor in the Caucasian ethnicity for developing breast cancer.