Longitudinal Oral Microbiome Sampling for BE

This study collects saliva samples over time to explore whether the bacteria in your mouth can help detect or predict Barrett's esophagus — a pre-cancerous change in the lining of the esophagus often linked to acid reflux. **You may be eligible if...** - You are 18 or older - You are scheduled for or have recently had an upper endoscopy (a camera exam of the esophagus and stomach) - You can produce a saliva sample - For Barrett's esophagus patients: You have confirmed Barrett's esophagus on endoscopy with intestinal changes on biopsy **You may NOT be eligible if...** - You have a history of head, neck, esophageal squamous cell, or gastric cancer - You have had prior esophageal or stomach surgery Talk to your doctor to see if this trial is right for you.