1. Department of Gastroenterology, Osaka City University Graduate School of Medicine, Osaka, Japan
2. Department of Premier Preventive Medicine, Osaka City University Graduate School of Medicine, Osaka, Japan
3. Department of Internal Medicine, Machida Gastrointestinal Hospital, Osaka, Japan
4. Department of Gastroenterology, Osaka City Juso Hospital, Osaka, Japan
5. Department of Diagnostic Pathology, Osaka City University Graduate School of Medicine, Osaka, Japan