Identification of loci of functional relevance to Barrett's esophagus and esophageal adenocarcinoma: Cross-referencing of expression quantitative trait loci data from disease-relevant tissues with genetic association data

PLoS One. 2019 Dec 31;14(12):e0227072. doi: 10.1371/journal.pone.0227072. eCollection 2019.

Abstract

Esophageal adenocarcinoma (EA) and its precancerous condition Barrett's esophagus (BE) are multifactorial diseases with rising prevalence rates in Western populations. A recent meta-analysis of genome-wide association studies (GWAS) data identified 14 BE/EA risk loci located in non-coding genomic regions. Knowledge about the impact of non-coding variation on disease pathology is incomplete and needs further investigation. The aim of the present study was (i) to identify candidate genes of functional relevance to BE/EA at known risk loci and (ii) to find novel risk loci among the suggestively associated variants through the integration of expression quantitative trait loci (eQTL) and genetic association data. eQTL data from two BE/EA-relevant tissues (esophageal mucosa and gastroesophageal junction) generated within the context of the GTEx project were cross-referenced with the GWAS meta-analysis data. Variants representing an eQTL in at least one of the two tissues were categorized into genome-wide significant loci (P < 5×10-8) and novel candidate loci (5×10-8 ≤ P ≤ 5×10-5). To follow up these novel candidate loci, a genetic association study was performed in a replication cohort comprising 1,993 cases and 967 controls followed by a combined analysis with the GWAS meta-analysis data. The cross-referencing of eQTL and genetic data yielded 2,180 variants that represented 25 loci. Among the previously reported genome-wide significant loci, 22 eQTLs were identified in esophageal mucosa and/or gastroesophageal junction tissue. The regulated genes, most of which have not been linked to BE/EA etiology so far, included C2orf43/LDAH, ZFP57, and SLC9A3. Among the novel candidate loci, replication was achieved for two variants (rs7754014, Pcombined = 3.16×10-7 and rs1540, Pcombined = 4.16×10-6) which represent eQTLs for CFDP1 and SLC22A3, respectively. In summary, the present approach identified candidate genes whose expression was regulated by risk variants in disease-relevant tissues. These findings may facilitate the elucidation of BE/EA pathophysiology.

Publication types

  • Meta-Analysis
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenocarcinoma / genetics*
  • Adenocarcinoma / pathology
  • Barrett Esophagus / genetics*
  • Barrett Esophagus / pathology
  • Esophageal Mucosa / pathology*
  • Esophageal Neoplasms / genetics*
  • Esophageal Neoplasms / pathology
  • Gene Expression Regulation, Neoplastic*
  • Genetic Predisposition to Disease
  • Genome-Wide Association Study
  • Humans
  • Polymorphism, Single Nucleotide
  • Proteins / genetics
  • Quantitative Trait Loci*
  • Repressor Proteins / genetics
  • Sodium-Hydrogen Exchanger 3 / genetics

Substances

  • LDAH protein, human
  • Proteins
  • Repressor Proteins
  • SLC9A3 protein, human
  • Sodium-Hydrogen Exchanger 3
  • ZFP57 protein, human

Supplementary concepts

  • Adenocarcinoma Of Esophagus

Grants and funding

Anne C. Böhmer received funding for this work by the BONFOR-program of the Medical Faculty, University of Bonn [O-149.0121]. Anne C. Böhmer is supported by the Diet-Body-Brain (DietBB) Competence Cluster in Nutrition Research funded by the Federal Ministry of Education and Research of Germany [01EA1809B]. Johannes Schumacher received support for this work from the Else Kröner Fresenius Stiftung [2013_A118]. Kerstin U. Ludwig is supported by the German Research Foundation (LU-1944/3-1). Markus M. Nöthen is a member of the DFG funded Excellence Cluster ImmunoSensation.