XRCC1 and breast cancer: However, a significant increase in breast cancer risk was seen among ever smoking women if they carried at least one XRCC1-399 Gln allele (OR 2.33, 95% CI 1.30–4.19, pint 0.025) or XPD-751 Gln/Gln genotype (OR 2.52, 95% CI 1.27–5.03, pint 0.011) compared to smoking women not carrying these genotypes.