1. Department of Gastroenterological and Transplant Surgery; Graduate School of Biomedical & Health Sciences; Hiroshima University; Hiroshima Japan
2. Department of Surgery; National Hospital Organization Kure Medical Center and Chugoku Cancer Center; Hiroshima Japan
3. Department of Epidemiology; Infectious Disease Control and Prevention; Graduate School of Biomedical & Health Sciences; Hiroshima University; Hiroshima Japan
4. Department of Anatomical Pathology; Hiroshima University Hospital; Hiroshima Japan