This study aims to elucidate the relationship between the microbiome, inflammation, and the microenvironment in Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC), with the end goal of developing a non-endoscopic testing strategy based on pathogenic factors to identify patients at highest risk for EAC. To accomplish this the investigators will enroll 100 patients with known BE (50 with dysplasia or EAC) and 50 subjects without BE undergoing upper endoscopy. Prior to endoscopy each subject will undergo three minimally invasive potential screening and surveillance tests: saliva (oral microbiome), breath test (exhaled volatile organic compounds), and tethered capsule sponge sampling (methylated DNA markers). The study will evaluate these novel tests in combination with clinical and anthropometric factors to describe an optimal strategy for BE screening and monitoring.