The XRCC1 protein is involved in the base excision repair pathway through interactions with other proteins. Polymorphisms in the XRCC1 gene may lead to variation in repair proficiency and confer inherited predisposition to cancer. We prospectively assessed the associations between polymorphisms and haplotypes in XRCC1 and breast cancer risk in a nested case-control study within the Nurses' Health Study (incident cases, n = 1004; controls, n = 1385). We further investigated gene-environment interactions between the XRCC1 variations and plasma carotenoids on breast cancer risk. We genotyped four haplotype-tagging single nucleotide polymorphisms (Arg194Trp, C26602T, Arg 399Gln, and Gln632Gln) in the XRCC1 gene. Five common haplotypes accounted for 99% of the chromosomes in the present study population of mostly Caucasian women. We observed a marginally significant reduction in the risk of breast cancer among 194Trp carriers. As compared with nocarriers, women with at least one 194Trp allele had a multivariate odds ratio of 0.79 (95% of the confidence interval, 0.60-1.04). The inferred haplotype harboring the 194Trp allele was more common in controls than in cases (6.6 versus 5.3%, P = 0.07). We observed that the Arg 194Trp modified the inverse associations of plasma α-carotene level (P, ordinal test for interaction = 0.02) and plasma β-carotene level (P, ordinal test for interaction = 0.003) with breast cancer risk. No suggestion of an interaction was observed between the Arg 194Trp and cigarette smoking. Our results suggest an inverse association between XRCC1 194Trp allele and breast cancer risk. The findings of the effect modification of the Arg 194Trp on the relations of plasma α- and β-carotene levels with breast cancer risk suggest a potential protective effect of carotenoids in breast carcinogenesis by preventing oxidative DNA damage.
|Original language||English (US)|
|Number of pages||6|
|State||Published - Dec 1 2003|
ASJC Scopus subject areas
- Cancer Research