Abstract 2613: Racial/Ethnic specific polygenic models of breast cancer risk

Abstract

Abstract Breast cancer is the most frequently diagnosed cancer and the second leading cause of cancer death in American women. Earlier family linkage studies have identified high-penetrance breast cancer genes, such as BRCA1, BRCA2, and TP53. Moreover, genes involved in DNA repair, such as CHEK2, ATM, BRIP and PALB2, have been associated with moderate breast cancer risk. Recent Genome-wide Association Studies (GWAS) have identified multiple single nucleotide polymorphisms (SNPs) associated with breast cancer risk. We evaluated whether breast cancer risk is associated with multiple SNPs in DNA damage signaling and repair and immune and inflammatory responses in addition to SNPs identified from GWAS. We hypothesize that targeting critical candidate pathways may yield important information regarding SNP-SNP interactions in breast cancer risk. We selected SNPs from DNA damage signaling and cell cycle control, base excision repair, nucleotide excision repair, double-strand break repair, mismatch repair, and immune and inflammatory responses. We have genotype results of 3,754 SNPs in 910 controls (763 Whites and 147 African Americans) and 793 breast cancer cases (667 Whites and 116 African Americans). 16.2% and 20.6% of controls and cases (respectively) had a first degree relative with breast cancer. 48% and 55.7% of the controls and cases (respectively) had their first child before or at the age of 24. 40.5% and 42.2% of the controls and cases (respectively) had a history of smoking. Our study results suggest that 6 SNPs were associated with breast cancer risk in Whites: (1) 2 SNPs from GWAS - rs3817198 in LSP1 (p<0.001) and rs3803662 in TNRC9 (p<0.001); (2) 2 SNPs from inflammation - rs1801157 in SDF-1 (p<0.001) and rs12720356 in Tyk2 (p<0.001) and (3) 2 SNPs from DNA repair and apoptosis - rs2992 in CHAF1A (p<0.0001) and rs2231301 in BCL2l2 (p<0.001). Only 1 SNP, rs1990760 in IFIH1 (p<0.01) was associated with breast cancer risk in African Americans. The IFIH1 gene was previously linked to Type 1 diabetes but not in cancer risk. There was significant trend in breast cancer risk with increasing numbers of risk genotypes for rs3817198, rs3803662, rs1801157, rs12720356, rs2992, and rs2231301 (p test for trend <0.0001) in Whites after adjustment for potential confounders. Our results suggest that multiple SNPs contribute to breast cancer risk in a racial/ethnic specific manner and larger studies are warranted to further evaluate our findings. More importantly, functional analysis is under way to corroborate the association of multiple SNPs with breast cancer risk. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2613. doi:1538-7445.AM2012-2613