1. Department of Gastroenterology; Murakami Memorial Hospital; Asahi University; Gifu; Japan
2. Division of Endoscopy; Kyoto Prefectural University of Medicine; Kyoto; Japan
3. Department of Gastroenterology; Kawasaki Medical School; Okayama; Japan
4. Department of Clinical Research and Informatics; International Clinical Research Center; Research Institute; Institute Medical Center of Japan; Tokyo; Japan
5. Department of Pathology; Niigata University; Niigata; Japan