1. Department of Gastroenterology, Southern TOHOKU General Hospital, Koriyama, Fukushima 963‑8563, Japan
2. Department of Radiation Oncology, Niigata Cancer Center Hospital, Niigata, Niigata 951‑8566, Japan
3. Department of Surgery, Sanjo General Hospital, Sanjo, Niigata 955‑0055, Japan
4. Department of Surgery, Niigata Prefectural Kamo Hospital, Kamo, Niigata 959‑1397, Japan
5. Department of Pathology, Niigata Medical Center Hospital, Niigata, Niigata 950‑2022, Japan