Large scale meta-analysis identifies new genetic risk loci for esophageal adenocarcinoma (EA) and the first EA risk locus independent of Barrett’s esophagus

Abstract

SUMMARY
Background: Esophageal adenocarcinoma (EA) represents one of the fastest rising oncological diseases in western countries. Barrett’s Esophagus (BE) is the premalignant precursor of EA. However, only a subset of BE patients develop EA, which complicates the clinical management in the absence of valid predictors.
Methods: Within an international consortium of groups involved in the genetics of BE/EA, we performed the first meta-analysis of all genome-wide association studies (GWAS) available (>10,000 BE/EA patients, >17,000 controls, all of European descent). The entire GWAS-data set was also analyzed using bioinformatics approaches in order to identify pathophysiologically relevant cellular pathways. Findings: We identified nine new disease loci for BE/EA (P<5×10-8) and thereby doubled the number of known risk loci. The strongest new risk locus implicates CFTR as BE/EA risk gene. Mutations in CFTR cause cystic fibrosis (CF), the most common recessive disorder in Europeans. Gastroesophageal reflux (GER) belongs to the phenotypic CF-spectrum and represents the main risk factor for BE/EA. Thus, the CFTR locus may trigger a common GER-mediated pathophysiology. The strongest disease pathways identified (P<10-6) belong to muscle cell differentiation and to mesenchyme development/differentiation, which fit with current pathophysiological BE/EA concepts. Furthermore, for the first time we identified an EA-specific association (P=1·6×10-8) near HTR3C/ABCC5 which is independent of BE development (P=0·45).
Interpretation: The identified disease loci and pathways reveal new insights into the etiology of BE and EA. Furthermore, the EA-specific association at HTR3C/ABCC5 may constitute a novel genetic marker for the prediction of transition from BE to EA.
Funding: US National Cancer Institute, US National Institutes of Health, National Health and Medical Research Council of Australia, Swedish Cancer Society, Medical Research Council of UK, Cambridge NIHR biomedical research centre, Cambridge Experimental Cancer
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Medicine Centre, Else Kröner Fresenius Stiftung, Wellcome Trust, Cancer Research UK, AstraZeneca UK, University Hospitals of Leicester, University of Oxford.