Shuichi Miyamoto1,2, Jun Ito1,2, Tomohiko R Ohya3. 1. Department of Gastroenterology and Hepatology, Hakodate Municipal Hospital, Hokkaido, Japan. 2. Department of Gastroenterology and Hepatology, Faculty of Medicine, Graduate School of Medicine, Hokkaido University, Hokkaido, Japan. 3. Department of Endoscopy, The Jikei University School of Medicine, Tokyo, Japan.