1. Department of Surgery, Tokyo Metropolitan Tama Medical Center, Fuchu‑shi, Tokyo 183‑8524, Japan
2. Department of Gastroenterology and Hepatology, Tokyo Metropolitan Tama Medical Center, Fuchu‑shi, Tokyo 183‑8524, Japan
3. Department of Pathology, Tokyo Metropolitan Tama Medical Center, Fuchu‑shi, Tokyo 183‑8524, Japan