1 Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan; Division of Gastroenterology and Hepatology, Department of Medicine, National University Hospital, Singapore; Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
2 Digestive Disease Center, Showa University Northern Yokohama Hospital, Yokohama, Japan.
3 Division of Gastroenterology and Hepatology, Department of Medicine, National University Hospital, Singapore; Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
4 Department of Pathology and Laboratory Medicine, Showa University Northern Yokohama Hospital, Kanagawa, Japan.