1. Department of Gastroenterology and Hepatology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan
2. Department of Gastroenterology, Kagawa Prefectural Central Hospital, Takamatsu 760-8557, Japan
3. Department of Gastroenterology, Sumitomo Besshi Hospital, Niihama 792-8543, Japan
4. Department of Internal Medicine, Fukuyama City Hospital, Fukuyama 721-8511, Japan
5. Department of Gastroenterology, Fukuyama Medical Center, Fukuyama 720-8520, Japan
6. Department of Internal Medicine, Hiroshima City Hiroshima Citizens Hospital, Hiroshima 730-8518, Japan
7. Department of Endoscopy, Shikoku Cancer Center, Matsuyama 791-0280, Japan
8. Department of Gastroenterology and Hepatology, Kurashiki Central Hospital, Kurashiki 710-8602, Japan
9. Department of Internal Medicine, Okayama Saiseikai General Hospital, Okayama 700-8511, Japan
10. Department of Pathology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700-8558, Japan