1. Rabin Medical Center, Tel Aviv University – Gastroenterology, Petach Tikva, Israel
2. Helios St. Josefs-Hospital – Gastroenterology, Bochum-Linden, Germany
3. Leiden University Medical Center – Gastroenterology, Leiden, The Netherlands
4. Division of Surgery and of Gastroenterology and Hepatology and Christian Doppler Laboratory on Molecular Cancer Chemoprevention, Medical University of Vienna, Vienna, Austria
5. Pomeranian Medical University – Pathology, Szczecin, Poland