1. Division of Gastroenterology and Epidemiology; University of California at San Diego School of Medicine; La Jolla CA
2. Data Coordinating Center; Johns Hopkins University; Baltimore MD
3. Division of Gastroenterology; St. Louis University; St. Louis MO
4. Department of Internal Medicine; Division of Internal Medicine; Division of Gastroenterology; Virginia Commonwealth University; Richmond VA
5. Department of Gastroenterology/Hepatology; Cleveland Clinic Foundation; Metro Health Clinical Center, Case Western Reserve School of Medicine; Cleveland OH
6. Division of Gastroenterology; University of California San Francisco; San Francisco CA
7. National Institute of Diabetes & Digestive & Kidney Diseases; Bethesda MD
8. Laboratory of Pathology; National Cancer Institutes; Bethesda MD
9. Sharp Memorial Hospital; Department of Pathology; University of California San Diego; San Diego CA