1. Department of Gastroenterological Surgery, Osaka University Graduate School of Medicine, Osaka 565‑0871, Japan
2. Department of Surgery, Osaka General Medical Center, Osaka 558‑8558, Japan
3. Department of Surgery, Kindai University Faculty of Medicine, Osaka 589‑8511, Japan
4. Department of Pathology, Graduate School of Medicine, Osaka University, Osaka 565‑0871, Japan
5. Department of Surgery and Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812‑8582, Japan