Abstract 2682: Analysis of polygenic risk score interaction with coal use and risk of lung adenocarcinoma among never-smoking women in Asia
Authors: Blechter Batel , Hsiung Chao Agnes , Yin Zhihua , Shu Xiao-Ou , Hosgood H. Dean , Wong Jason Y.Y , Shi Jianxin , Hu Wei , Bassig Bryan , Seow Wei Jie , Gao Yu -ang , Cai Qiuyin , Xiang Yong-Bing , Chang I-Shou , Zhou Baosen , Zheng Wei , Lee Kyoung-Mu , Chanock Stephen , Chatterjee Nilanjan , Rothman Nathaniel , Lan Qing 
Published: August 2019

Abstract
Background: Accounting for approximately 1.76 million annual deaths worldwide, lung cancer is a significant global health burden. While smoking is the most common cause of lung cancer, up to 25% of all lung cancer patients worldwide are never smokers. Lung cancer is the leading cause of cancer mortality in China, where most women do not smoke, making women in Asia an ideal population to study. Previously conducted genome-wide association studies (GWAS) of lung cancer risk among never-smoking women in Asia identified 10 lung cancer susceptibility loci. Indoor air pollution from coal burned for home cooking and heating is known to contain lung carcinogens and has been found to be causally associated with lung cancer. In the current analysis, we evaluated gene-environment interaction between a polygenic risk score (PRS) and coal use in relation to lung adenocarcinoma.
Methods: Three studies (Taiwan, Shanghai, Shenyang) from the Female Lung Cancer Consortium in Asia (FLCCA) were used for the primary analysis (1,419 cases; 1,446 controls). A replication study was conducted using samples from Xuanwei, China (159 cases; 572 controls), where lung cancer rates for never-smokers are among the highest in the world and attributed to widespread coal use. We calculated a PRS as the weighted sum of the risk allele counts across the 10 loci, and modeled PRS as a continuous variable scaled by the standard deviation in controls. Logistic regression was used to estimate the main effects of the PRS and coal use, and a likelihood ratio test was used to evaluate the interaction. Models were adjusted for age (&lt;40, 40-49, 50-59, 60-69, ≥70 years), study, and significant eigenvectors.
Results: Coal use was associated with an increased risk of lung adenocarcinoma (OR=1.31, 95% CI: 1.01-1.68). We observed an exposure-response relationship between PRS and lung adenocarcinoma (p-trend= 2x10-16) and found a significant multiplicative interaction between PRS and coal use (p-interaction= 0.005). The association between PRS and lung adenocarcinoma was significantly higher among the never coal users (OR=1.68, 95% CI: 1.52-1.86) compared to ever coal users in the three studies (OR=1.24, 95% CI: 1.03-1.50) (p-interaction=0.005), as well as between never coal users in the three studies and ever coal users in Xuanwei (OR=1.25, 95% CI: 1.04-1.49) (p-interaction=0.004).
Conclusion: We observed an antagonistic interaction between PRS and coal use with lung adenocarcinoma, where the genetic effect was attenuated among those exposed to coal combustion in the home. We replicated the finding in Xuanwei. These results suggest that the pathogenesis of lung cancer among never-smoking women in Asia differs by exposure to coal combustion emissions and provides one of the few examples of sub-multiplicative gene-environment interactions in the cancer literature.
Citation Format: Batel Blechter, Chao Agnes Hsiung, Zhihua Yin, Xiao-Ou Shu, H. Dean Hosgood, Jason Y.Y Wong, Jianxin Shi, Wei Hu, Bryan Bassig, Wei Jie Seow, Yu -ang Gao, Qiuyin Cai, Yong-Bing Xiang, I-Shou Chang, Baosen Zhou, Wei Zheng, Kyoung-Mu Lee, Stephen Chanock, Nilanjan Chatterjee, Nathaniel Rothman, Qing Lan. Analysis of polygenic risk score interaction with coal use and risk of lung adenocarcinoma among never-smoking women in Asia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2682.