This study is to identify potential biomarkers for the early detection of Barrett's Esophagus, esophageal carcinoma (both adenocarcinoma and squamous cell carcinoma). Esophageal and gastric cytology will be collected via sponge capsule. Candidate genes will be tested with DNA isolated from these samples in order to identify optimal biomarkers to differentiate between Barrett's esophagus and esophageal/gastric cancer versus normal esophageal/gastric tissue.

