Genes involved in the nucleotide excision repair (NER) pathway, which removes bulky DNA adducts, are potential low-penetrance cancer susceptibility genes. We recently reported an association between detectable polycyclic aromatic hydrocarbon (PAH)-DNA adducts and breast cancer risk. Using a population-based breast cancer case-control study on Long Island, New York, we examined whether polymorphisms in NER genes modified the association between PAH-DNA adducts and breast cancer risk. We examined polymorphisms in ERCC1 (3 ¶-untranslated region 8092C/A), XPA (5 ¶-untranslated region À4G/A), XPD (Asp 312 Asn in exon 10), XPF (Arg 415 Gln in exon 8), and XPG (Asp 1104 His in exon 15) in 1,053 breast cancer cases and 1,102 population-based controls. The presence of at least one variant allele in XPD was associated with a 25% increase in the odds ratio [OR, 1.25; 95% confidence interval (95% CI), 1.04-1.50] for breast cancer. The increase associated with homozygosity of the variant alleles for XPD and ERCC1 was stronger among those with detectable PAH-DNA adduct levels (OR, 1.83; 95% CI, 1.22-2.76 and OR, 1.92; 95% CI, 1.14-3.25 for detectable versus nondetectable adducts and homozygous wild-type genotype for XPD and ERCC1, respectively). We found no association between XPA, XPF, and XPG genotypes, PAH-DNA adducts, and breast cancer risk. When we combined genotypes for these NER pathway genes, there was a significant trend for increasing breast cancer risk with increasing number of putative high-risk alleles. Overall, this study suggests that the risk of breast cancer may be elevated among women with polymorphisms in NER pathway genes and detectable PAH-DNA adducts. (Cancer Epidemiol Biomarkers Prev 2007;16(10):2033 -41)

To evaluate the role of oxidative stress in breast cancer, we measured urinary levels of 15-F 2t -isoprostane (15-F 2t -IsoP) and 8-oxodeoxyguanosine (8-oxodG) in 400 cases and 401 controls, participants of the Long Island Breast Cancer Study Project. We also analyzed the effect of different factors that are associated with oxidative stress and might influence 15-F 2t -IsoP and 8-oxodG levels. We observed a statistically significant trend in breast cancer risk with increasing quartiles of 15-F 2t -IsoP levels [odds ratio (OR), 1.25; 95% confidence interval (95% CI), 0.81-1.94; OR, 1.53; 95% CI, 0.99-2.35; OR, 1.88; 95% CI, 1.23-2.88, for the 2nd, 3rd, and 4th quartile relative to the lowest quartile, respectively; P trend = 0.002]. Although it is possible that increased levels may reflect the stress associated with recent treatment, the positive association was also observed when the analyses were restricted to case women for whom chemotherapy and radiation therapy had not yet been initiated at the time of the urine collection. The association with the highest quartile compared with lowest quartile of 15-F 2t -IsoP was similar across strata of age, physical activity, fruit and vegetable intake, alcohol intake, cigarette smoking, body mass index, and menopausal status. We did not observe any association of breast cancer risk with 8-oxodG levels, but when cases with radiation treatment were removed from the analysis, a significant inverse trend (P = 0.04) was observed. Among controls, levels of 15-F 2t -IsoP were higher among current cigarette smokers but did not differ by the amount of physical activity, fruit and vegetable intake, alcohol intake, body mass index, and menopausal status. Among controls, levels of 8-oxodG were higher among postmenopausal women and current and former cigarette smokers but did not differ by the other factors. In summary, our results suggest that urinary markers of lipid peroxidation and oxidative DNA damage may be associated with breast cancer risk. (Cancer Epidemiol Biomarkers Prev 2006;15(4):639 -44)

Interindividual differences in DNA repair capacity (DRC) may play a critical role in breast cancer risk. Previously, we determined that DRC measured via removal of in vitro -induced benzo[a]pyrene diolepoxide-DNA adducts in lymphoblastoid cell lines was lower in cases compared with controls among sisters discordant for breast cancer from the Metropolitan New York Registry of Breast Cancer Families. We have now determined genotypes for seven single nucleotide polymorphisms in five nucleotide excision repair genes, including Xeroderma pigmentosum complementation group A (XPA +62T>C), group C (XPC Lys939Gln and Ala499Val), group D (XPD Asp312Asn and Lys751Gln), and group G (XPG His1104Asp) and ERCC1 (8092 C>A) in a total of 160 sister pairs for whom DRC phenotype data were available. Overall, there were no statistically significant differences in average DRC for most of the genotypes. A final multivariate conditional logistic model, including three single nucleotide polymorphisms (XPA +62T>C, XPC Ala499Val, and XPG His1104Asp) and smoking status, only modestly predicted DRC after adjusting for case-control status and age of blood donation. The overall predictive accuracy was 61% in the model with a sensitivity of 78% and specificity of 39%. These findings suggest that those polymorphisms we have investigated to date in nucleotide excision repair pathway genes explain only a small amount of the variability in DRC. (Cancer Epidemiol Biomarkers Prev 2006;15(9):1614 -9)

Deficient DNA repair capacity is associated with increased breast cancer risk.

BackgroundPrevious studies have suggested that polycyclic aromatic hydrocarbons (PAHs) may be associated with breast cancer. However, the carcinogenicity of PAHs on the human breast remains unclear. Certain carcinogens may be associated with specific mutation patterns in the p53 tumor suppressor gene, thereby contributing information about disease etiology.ObjectivesWe hypothesized that associations of PAH-related exposures with breast cancer would differ according to tumor p53 mutation status, effect, type, and number.MethodsWe examined this possibility in a population-based case–control study using polytomous logistic regression. As previously reported, 151 p53 mutations among 859 tumors were identified using Surveyor nuclease and confirmed by sequencing.ResultsWe found that participants with p53 mutations were less likely to be exposed to PAHs (assessed by smoking status in 859 cases and 1,556 controls, grilled/smoked meat intake in 822 cases and 1,475 controls, and PAH–DNA adducts in peripheral mononuclear cells in 487 cases and 941 controls) than participants without p53 mutations. For example, active and passive smoking was associated with p53 mutation–negative [odds ratio (OR) = 1.55; 95% confidence interval (CI), 1.11–2.15] but not p53 mutation–positive (OR = 0.77; 95% CI, 0.43–1.38) cancer (ratio of the ORs = 0.50, p < 0.05). However, frameshift mutations, mutation number, G:C→A:T transitions at CpG sites, and insertions/deletions were consistently elevated among exposed subjects.ConclusionsThese findings suggest that PAHs may be associated with specific breast tumor p53 mutation subgroups rather than with overall p53 mutations and may also be related to breast cancer through mechanisms other than p53 mutation.