The goal of the proposed research is to investigate the molecular mechanisms of racial disparity in Barrett's esophagus (BE), the premalignant lesion of esophageal adenocarcinoma. Specifically, the investigators hypothesize that environmental factors, genetic factors, and potentially gene environment interactions play crucial roles in the observed racial disparity in developing Barrett's esophagus.

Patients are recruited through UNC hospitals prior to scheduled esophagogastroduodenoscopy (EGD). Participants complete a questionnaire, have body measurements obtained, and have blood, biopsies, and gastric aspirate collected. Participants also complete a 24 hour pH impedance test.

The goal of the proposed research is to investigate the molecular mechanisms of racial disparity in Barrett's esophagus, the premalignant lesion of esophageal adenocarcinoma. Specifically, the investigators hypothesize that environmental factors, genetic factors, and potentially gene environment interactions play crucial roles in the observed racial disparity in developing Barrett's esophagus.

Participants: Patients aged 18-80 presenting at the Gastrointestinal (Gl) Endoscopy Clinic at UNC-Chapel Hill for elective upper endoscopy with a primary or secondary indication of reflux symptoms.

Procedures (methods): Endoscopic biopsy, pH impedance and sampling of gastric secretions will be performed according to our standard protocol. A series of questionnaires assessing demographics, environmental exposure (e.g., smoking, drinking), markers of socioeconomic status (SES), body measurement, previous health history, and gastroesophageal reflux disease (GERD) symptomatology will be administered to our subjects.

Inclusion Criteria:

• Aged 18 to 80
• Self-identify is "not Hispanic or Latino" and either "African American" or "White."
• Cases will be eligible for inclusion if they have endoscopically evident Barrett's Esophagus (BE) of any length. BE will be defined as: 1) Any upward displacement of the squamocolumnar junction noted on endoscopy such that the interface of squamous and columnar mucosa is no longer at the interface of the most distal tubular esophagus and the proximal gastric folds. The characteristic pale pink coloration of the squamous epithelium in these areas will be replaced by the darker salmon color commonly seen in BE. 2) Histologic interpretation of biopsies consistent with intestinal columnar metaplasia containing goblet cells, which are positively stained by Alcian blue staining as barrel-shaped cells.
• Controls will be eligible for inclusion if they have classic symptoms of gastroesophageal reflux disease (GERD), but no endoscopic or histological evidence of BE. Both erosive and non-erosive GERD will be eligible. Because we expect GERD to outnumber BE and patients with GERD may be slightly less willing to participate in the study than patients with BE (based on recruitment for the studies noted above), we plan to randomly sample one fourth of eligible controls. If approximately 20% fewer GERD than BE participate, a final study population with an approximately 1:2 BE to GERD ratio will be achieved. Oversampling of patients with GERD will improve study power.

Exclusion Criteria:

• Patients who are unable to read or comprehend the informed consent or written questionnaires;
• Patients who are status post partial or complete esophageal resection;
• Patients with prevalent BE who have undergone endoscopic ablation;
• Patients found to have high-grade dysplasia or esophageal cancer on the index endoscopy;
• Patients with surgical anti-reflux procedures;
• Patients of races other than Caucasian and African Americans;
• Pregnant women.
• Patients 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).

The source of the study population will be patients aged 18-80 presenting at the gastrointestinal (Gl) Endoscopy Clinic at UNC-Chapel Hill for elective upper endoscopy with a primary or secondary indication of reflux symptoms. Any patient undergoing endoscopy with classic reflux symptoms is eligible to participate in the study. These symptoms include a substernal chest burning or warmth, a "waterbrash" sensation, regurgitation, or any chest pain worst when supine or after meals.

Race will be self-identified race or ethnicity (SIRE) from a researcher-provided list. According to the NIH Policy on Reporting Race and Ethnicity Data published in August 8, 2001 (NOT-OD-01-053), we will "use two separate questions with ethnicity information collected first followed by the option to select more than one racial designation." Patients in this study should be "Not Hispanic or Latino", and either "African American" or "White".