1. Department of Digestive Tract and General Surgery; Saitama Medical Center, Saitama Medical University; Saitama Japan
2. Department of Esophageal and General Surgery; Tokyo Medical and Dental University; Tokyo Japan
3. Department of Pathology; Saitama Medical Center, Saitama Medical University; Saitama Japan
4. Research Team for Geriatric Pathology; Tokyo Metropolitan Institute of Gerontology; Tokyo Japan