1. Department of Surgery, School of Medicine, Toho University, Tokyo 143‑8541, Japan
2. Division of Gastroenterological Surgery, Chiba Cancer Center, Chiba 260‑8717, Japan
3. Department of Clinical Oncology, Graduate School of Medicine, Toho University, Tokyo 143‑8541, Japan
4. Medical and Biological Laboratories Co., Ltd., Nagoya, Aichi 460‑0008, Japan