1. Department of Gastroenterology and Hepatology, Netherlands Cancer Institute, Amsterdam, The Netherlands
2. Department of Gastroenterology and Hepatology, Leiden University Medical Center, Leiden, The Netherlands, Foundation for the Detection of Hereditary Tumours, Leiden, The Netherlands
3. Department of Gastroenterology and Hepatology, Amsterdam University Medical Centers, University of Amsterdam, Cancer Center Amsterdam, Amsterdam, The Netherlands
4. Gastroenterology Department, Hospital Clínic de Barcelona, Barcelona, Spain
5. Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Institut d’Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Universitat de Barcelona, Barcelona, Spain
6. Department of Cancer Prevention, The Maria Sklodowska-Curie Memorial Cancer Center and Institute of Oncology, Warsaw, Poland
7. Department of Gastroenterology, Hepatology and Clinical Oncology, Medical Centre for Postgraduate Education, Warsaw, Poland
8. Department of Health Management and Health Economics, University of Oslo, Oslo, Norway
9. Polyposis Registry, St. Mark’s Hospital, Harrow, United Kingdom
10. Department of Surgery and Cancer, Imperial College London, London, United Kingdom
11. Department of Medicine I, University Medical Center Mainz, Mainz, Germany
12. Department of Medical and Surgical Sciences, University of Bologna, Bologna, Italy
13. Gastroenterology and Endoscopy Unit, Hospices Civils de Lyon, Hôpital E. Herriot, Lyon, France
14. Department of Surgery, Amsterdam University Medical Centers, University of Amsterdam, Cancer Center Amsterdam, , Amsterdam, The Netherlands
15. Department of Clinical Genetics, Erasmus University Medical Center, Erasmus MC Cancer Institute, Rotterdam, The Netherlands
16. Department of Gastroenterology, Hospital General Universitario de Alicante, Instituto de Investigación Sanitaria y Biomédica de Alicante, ISABIAL, Alicante, Spain