1. Latin American Collaborative Research Center of Tokyo Medical and Dental University; Santiago Chile
2. Department of Digestive and General Surgery; Tokyo Medical and Dental University; Tokyo Japan
3. Department of Human Pathology; Tokyo Medical and Dental University; Tokyo Japan
4. Unit of Coloproctology; Las Condes Clinic; Santiago Chile
5. Department of Digestive Endoscopy, Magallanes Hospital; Punta Arenas Chile
6. Department of Gastroenterology, Dr. Eduardo Pereira Hospital; Valparaiso Chile
7. Chilean-Japanese Institute for Digestive Diseases, San Borja Arriaran Hospital; Santiago Chile
8. Department of Surgical Specialties; Tokyo Medical and Dental University; Tokyo Japan