1. Department of Gastroenterological Surgery, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
2. Division of Health Science, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
3. Department of Surgery, Yao Municipal Hospital, Osaka 581‑0069, Japan
4. Department of Surgery, Kansai Rosai Hospital, Hyogo 660-8511, Japan
5. Department of Surgery, Osaka�Police Hospital, Osaka 543-0035, Japan
6. Departments of Gastroenterology and Hepatology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
7. Department of Pathology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan