Abstract 1276: Gene-environment interaction relevant to estrogen and risk of breast cancer

Abstract

Abstract Introduction: Many established reproductive risk factors for breast cancer are mediated by hormonal mechanisms, and most parts are involved in estrogens. In addition, the estrogen level controlled by genetic factors might be a sort of determinants to breast cancer risk involving estrogen metabolism. This study aims to examine gene and environment interaction (GxE) between candidate genes which are involved in estrogen metabolism and environmental factors which are related to estrogen exposure. Methods: GxE analyses were conducted in the Korean 1,970 breast cancer cases and 2,052 controls which were recruited in the Seoul Breast Cancer Study (SEBCS), a multicenter case control study. 137 candidate genes involved in estrogen metabolism were searched from couple of databases and 11,555 SNPs (2,472 typed SNPs and 9,083 imputed SNPs) from the range of candidate genes were included in GxE analyses with 8 established environmental factors. Statistical analyses were performed by using GxEScan (ver. Beta 0.4.0; http://biostats.usc.edu/software) for GxE test. Results: There were three significant interaction between 11,555 SNPs and 8 environmental factors. Firstly, interaction rs851998 nearby ESR1 with height was shown in the GE|2df model (p-2df = 1.1x10-4) This SNP had protective effect marginally (ORG = 0.82, 95% CI: 0.75-0.90) and further protective effect for women whose height is smaller than 160cm (OR G | height ≥ 160cm = 0.78, 95% CI: 0.70-0.87, p = 1.09x10-5). Second interaction was shown between rs13035764 of NCOA1 and age at menarche in the GE|2df model (p-2df = 1.2x10-3). This SNP also had protective effect marginally (ORG = 0.85, 95% CI: 0.77-0.97) and more protective effect when age at menarche is 14 years and over (OR G | age at menarche ≥ 14years = 0.82, 95% CI: 0.73-0.97, p=3.6x10-4). Lastly, there was marginally significant interaction between rs4140979 of FSHR and age at first full term pregnancy (FFTP) in the EDGxE model. Although this SNP had no marginal effect, qualitative interaction was shown with FFTP (OR G | FFTP < 27years = 0.88, 95% CI: 0.78-1.00, p=0.0482; OR G | Nulliparity or FFTP ≥ 27 years = 1.30, 95% CI: 1.10-1.53, p=0.002). Conclusion: Three significant interactions were identified by focusing two step methods. Replication should be performed in the independent and larger population due to statistical limitation. Citation Format: JooYong Park, Ji-Yeob Choi, Seokang Chung, Nan Song, Sue K Park, Wonshik Han, Dong-Young Noh, Sei-Hyun Ahn, Mi-Kyung Kim, Keun-Young Yoo, Wei Zheng, Daehee Kang. Gene-environment interaction relevant to estrogen and risk of breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1276. doi:10.1158/1538-7445.AM2017-1276