1. Department of Molecular Biology, Sapporo Medical University School of Medicine, Sapporo, Japan
2. Department of Gastroenterology and Hepatology, Sapporo Medical University School of Medicine, Sapporo, Japan
3. Department of Pathology, Sapporo Medical University School of Medicine, Sapporo, Japan
4. Department of Digestive Disease Center, Akita Red Cross Hospital, Akita, Japan
5. Department of Molecular Diagnostic Pathology, School of Medicine, Iwate Medical University, Morioka, Japan