1. Department of Infectious, Respiratory, and Digestive Medicine, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan.
2. Department of Digestive and General Surgery, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan.
3. Department of Endoscopy, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan.
4. Department of Pathology, Seirei Yokohama Hospital, Kanagawa, Japan.
5. Department of Pathology and Oncology, Graduate School of Medicine, University of the Ryukyus, Okinawa, Japan.