1. Faculty of Medicine; University of Latvia; Riga Latvia
2. Riga East University Hospital; Riga Latvia
3. Digestive Diseases Centre GASTRO; Riga Latvia
4. University of Leeds; Leeds UK
5. Division of Clinical Epidemiology and Aging Research; German Cancer Research Center (DKFZ); Heidelberg Germany
6. Division of Preventive Oncology; German Cancer Research Center (DKFZ) and National Center for Tumor Diseases (NCT); Heidelberg Germany
7. German Cancer Consortium; German Cancer Research Center (DKFZ); Heidelberg Germany