1. Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Japan
2. Department of Hematology and Oncology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Japan
3. Department of Pathology, Okayama University Hospital, Japan
4. Department of Practical Gastrointestinal Endoscopy, Okayama University Hospital, Japan