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Background: Important risk factors for esophageal adenocarcinoma and its precursor, Barrett's esophagus, include gastroesophageal reflux disease, obesity, and cigarette smoking. Recently, genome-wide association studies have identified seven germline single-nucleotide polymorphisms (SNP) that are associated with risk of Barrett's esophagus and esophageal adenocarcinoma. Whether these genetic susceptibility loci modify previously identified exposure-disease associations is unclear. Methods: We analyzed exposure and genotype data from the BEACON Consortium discovery phase GWAS, which included 1,516 esophageal adenocarcinoma case patients, 2,416 Barrett's esophagus case patients, and 2,187 control participants. We examined the seven newly identified susceptibility SNPs for interactions with body mass index, smoking status, and report of weekly heartburn or reflux. Logistic regression models were used to estimate ORs for these risk factors stratified by SNP genotype, separately for Barrett's esophagus and esophageal adenocarcinoma. Results: The odds ratio for Barrett's esophagus associated with at least weekly heartburn or reflux varied significantly with the presence of at least one minor allele of rs2687201 (nominal P = 0.0005, FDR = 0.042). ORs (95% CIs) for weekly heartburn or reflux among participants with 0, 1, or 2 minor alleles of rs2687201 were 6.17 (4.91-7.56), 3.56 (2.85-4.44), and 3.97 (2.47-6.37), respectively. No statistically significant interactions were observed for smoking status and body mass index. Conclusion: Reflux symptoms are more strongly associated with Barrett's esophagus risk among persons homozygous for the major allele of rs2687201, which lies approximately 75 kb downstream of the transcription factor gene FOXP1. Impact: The novel gene-exposure interaction discovered in this study provides new insights into the etiology of esophageal adenocarcinoma. [ABSTRACT FROM AUTHOR]

Background: Several cancer-associated loci identified from genome-wide association studies (GWAS) have been associated with risks of multiple cancer sites, suggesting pleiotropic effects. We investigated whether GWAS-identified risk variants for other common cancers are associated with risk of esophageal adenocarcinoma (EA) or its precursor, Barrett's esophagus. Methods: We examined the associations between risks of EA and Barrett's esophagus and 387 SNPs that have been associated with risks of other cancers, by using genotype imputation data on 2,163 control participants and 3,885 (1,501 EA and 2,384 Barrett's esophagus) case patients from the Barrett's and Esophageal Adenocarcinoma Genetic Susceptibility Study, and investigated effect modification by smoking history, body mass index (BMI), and reflux/heartburn. Results: After correcting for multiple testing, none of the tested 387 SNPs were statistically significantly associated with risk of EA or Barrett's esophagus. No evidence of effect modification by smoking, BMI, or reflux/heartburn was observed. Conclusions: Genetic risk variants for common cancers identified from GWAS appear not to be associated with risks of EA or Barrett's esophagus. Impact: To our knowledge, this is the first investigation of pleiotropic genetic associations with risks ofEAand Barrett's esophagus. [ABSTRACT FROM AUTHOR]