The Microbiome, Bile Acids, and Notch in Barrett's Esophagus (BE)

Inclusion Criteria: All subjects: * Scheduled for an upper endoscopy * Taking stable dose of a proton pump inhibitor at least once daily for 1 months prior to enrollment * Eighteen years of age or older * Able to give informed consent Barrett's esophagus subjects only: * Histologically confirmed BE (defined as endoscopically- suspected BE with intestinal metaplasia with goblet cells on esophageal biopsies) * Maximal BE length ≥ 2 cm (Prague criteria: any C, M≥2) Exclusion Criteria: All subjects: * History of head and neck cancer or esophageal or gastric cancer (except esophageal intramucosal adenocarcinoma) * History of esophageal or gastric surgery * Use of antibiotics or immunosuppressants within 1 month prior to endoscopy Barrett's esophagus subjects only: • History of prior endoscopic therapy for BE, except a history of prior endoscopic mucosal resection (EMR) of focal lesions withoutsubsequent ablative therapy is permitted