1 Department of Gastroenterology and Hepatology, International University of Health and Welfare, School of Medicine, Chiba, Japan.
2 Center of Excellence in Endoscopy for Gastrointestinal Oncology, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand.
3 Division of Gastroenterology and Hepatology, Department of Medicine, Nihon University School of Medicine, Tokyo, Japan.