1. Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Japan
2. Department of Internal Medicine, Fukuyama City Hospital, Japan
3. Department of Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Japan
4. Department of Pathology, Okayama University Hospital, Japan
5. Department of Endoscopy, Okayama University Hospital, Japan