Detection of Mutations in Barrett’s Esophagus Before Progression to High-Grade Dysplasia or Adenocarcinoma

Abstract

Barrett's esophagus (BE) is the greatest risk factor for esophageal adenocarcinoma (EAC), but only a small proportion of patients with BE develop cancer. Biomarkers might be able to identify patients at highest risk of progression. We investigated genomic differences in surveillance biopsies collected from patients whose BE subsequently progressed compared to patients whose disease did not progress. We performed a retrospective case-control study of 24 patients with BE that progressed to high-grade dysplasia (HGD, n= 14) or EAC (n= 10). The control group (n= 73, called non-progressors) comprised patients with BE and at least 5 years of total endoscopic biopsy surveillance without progression to HGD or EAC. From each patient, we selected a single tissue sample obtained more than 1 year before progression (cases) or more than 2 years before the end of follow-up (controls). Pathogenic mutations, gene copy numbers, and ploidy were compared between samples from progressors and non-progressors. TP53 mutations were detected in 46% of samples from progressors and 5% of non-progressors. In this case-control sample set, TP53 mutations in BE tissues increased the adjusted risk of progression 13.8-fold (95% confidence interval, 3.2-61.0) (P < .001). We did not observe significant differences in ploidy or copy-number profile between groups. We identified 147 pathogenic mutations in 57 distinct genes-the average number of pathogenic mutations was higher in samples from progressors (n= 2.5) than non-progressors (n= 1.2) (P < .001). TP53 and other somatic mutations were recurrently detected in samples with limited copy-number changes (aneuploidy). In genomic analyses of BE tissues from patients with or without later progression to HGD or EAC, we found significantly higher numbers of TP53 mutations in BE from patients with subsequent progression. These mutations were frequently detected before the onset of dysplasia or substantial changes in copy number.