1. Gastroenterology, Toyoshima Endoscopy Clinic, Tokyo, Japan
2. Department of Gastroenterology and Hepatology, International University of Health and Welfare, Mita Hospital, Tokyo, Japan
3. Gastroenterology, Sakitani Endoscopy Clinic, Chiba-Tsudanuma, Japan
4. Department of Gastroenterology and Hepatology, Tokai University School of Medicine, Tokyo, Japan
5. Department of Gastroenterology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
6. Department of Surgical Oncology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan