Abstract 21: Variations in DNA repair gene expression and breast cancer risk in the New York site of the Breast Cancer Family Registry.

Reduced DNA repair capacity contributes to genomic instability, a hallmark of carcinogenesis. The link between DNA repair capacity and cancer is especially relevant in breast cancer, where women with suboptimal repair capacity have been reported to have up to a five-fold increase in breast cancer risk compared to women with greater repair capacity. We investigated the expression level of several DNA repair-related genes and their association with breast cancer risk among participants of the New York site of the Breast Cancer Family Registry. We examined RNA from viable mononuclear cells in 213 sisters (N=511 women). A total of five genes, ATM, BRCA1, MSH2, MUTYH and XPC, were selected and assayed using Taqman gene expression kits from Applied Biosystems. With the exception of BRCA1, expression of these genes was lower, but not statistically significant, among sisters with breast cancer compared with their unaffected sisters. Using generalized estimating equations (GEE), we found that individuals in the lowest quartile of expression for MSH2, a gene involved in DNA mismatch repair, had significantly higher odds of breast cancer compared to individuals in the highest quartile of expression, adjusting for age at blood draw (OR=1.82, 95% CI=1.11, 2.99). These findings suggest that a reduction in MSH2 expression compromises mismatch repair capacity and, thereby, increases breast cancer susceptibility.

Citation Format: Maya Kappil, Mary Beth Terry, Yuyan Liao, Regina Santella. Variations in DNA repair gene expression and breast cancer risk in the New York site of the Breast Cancer Family Registry. [abstract]. In: Proceedings of the AACR Special Conference on Post-GWAS Horizons in Molecular Epidemiology: Digging Deeper into the Environment; 2012 Nov 11-14; Hollywood, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2012;21(11 Suppl):Abstract nr 21.