1. Department of Medicine I; University Clinic of Bonn; Bonn; Germany
2. Department of Cellular and Molecular Pathology; German Cancer Research Center; Heidelberg; Germany
3. Department of Medicine III; University Hospital Aachen; Aachen; Germany
4. Department of Medicine II; Saarland University Hospital; Saarland; Germany
5. Department of Gastroenterology and Hepatology; University Hospital Essen; Essen; Germany
6. Division of Gastroenterology and Hepatology; University Hospital of Zurich; Zurich; Switzerland