The investigators propose a study comparing the morphological and functional aspects of the neosquamous epithelium (NSE) after ablative therapy for dysplastic Barrett's esophagus (BE) to that of native squamous epithelium in normal controls as well as gastroesophageal reflux disease (GERD), non-Barrett's Esophagus (BE) subjects.

Purpose: We propose a study comparing the morphological and functional aspects of the neosquamous epithelium (NSE) after ablative therapy for dysplastic Barrett's esophagus (BE) to that of native squamous epithelium in normal controls as well as gastroesophageal reflux disease (GERD), non-BE subjects.

Participants: Eligible subjects will be women and men between the ages of 18-80, with one of the following:

1. Two or greater cm of dysplastic BE, who will undergo or have undergone radiofrequency ablation for BE at UNC, or
2. Diagnosed with GERD per a gastrointestinal (GI) physician undergoing upper endoscopy for other indications at UNC, or
3. Non-GERD controls per a GI physician with normal esophageal mucosa undergoing upper endoscopy for other indications at UNC.

Procedures (methods): Esophageal biopsies will be obtained specifically for research purposes before ablation therapy or, in subjects not receiving ablative therapy, after completion of the clinically indicated procedure and before withdrawal of the endoscope. Information from the medical record or from patient interview will be obtained regarding diagnosis (Barrett's esophagus, GERD, etc), and a questionnaire administered regarding the duration and frequency of reflux symptoms and complications of reflux disease. Subjects who are enrolled in the pre-ablation group will have additional biopsies and questionnaires administered during scheduled follow-up visits. On the last follow-up visit, this group will also undergo impedance-pH testing using standard methods, to assess for degree of control of esophageal acid exposure, and for number, duration and symptom correlation of non-acid reflux events.

Inclusion:

Eligible subjects will be mentally competent women and men between the ages of 18-80, able to speak and read English and who meet one of the following criteria:

• Two or greater cm of dysplastic Barrett's Esophagus (BE), who will undergo or have undergone radiofrequency ablation (RFA) for BE at the University of North Carolina, Chapel Hill (UNC), or
• Diagnosed with gastroesophageal reflux disease (GERD) per a GI physician undergoing upper endoscopy (EGD) for other indications at UNC, or
• Non-GERD controls per a GI physician with normal esophageal mucosa undergoing upper endoscopy for other indications at UNC.

Exclusion:

• Subjects with a bleeding diathesis or other contraindication of endoscopic biopsy.
• Current use of warfarin, heparin, and/or low molecular weight heparin (requires discontinuation of medication 5 days prior to and 7 days after EGD).
• Pregnant women

Potential subjects will be identified by their gastrointestinal (GI) physician and approached by a study coordinator, nurse, or their GI physician regarding this study on the day of their scheduled procedure at UNC hospitals/GI clinic.