1. Department of Gastroenterology, Osaka Metropolitan University Graduate School of Medicine, Osaka 545‑8585, Japan
2. Department of Clinical Oncology, Osaka City General Hospital, Osaka 534‑0021, Japan
3. Department of Gastroenterology, Machida Gastrointestinal Hospital, Osaka 557‑0001, Japan
4. Department of Surgery, Osaka Ekisaikai Hospital, Osaka 550‑0022, Japan