1. Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Japan
2. Department of Practical Gastrointestinal Endoscopy, Okayama University Hospital, Japan
3. Department of Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Japan
4. Department of Internal Medicine, Japanese Red Cross Himeji Hospital, Japan