1. Institute of Pathology University of Cologne Cologne Germany
2. Department of General, Visceral and Cancer Surgery University of Cologne Cologne Germany
3. Center for Esophageal and Gastric Surgery AGAPLESION Markuskrankenhaus Frankfurt am Main Germany
4. Department of Radiation Oncology University of Cologne Cologne Germany
5. Service de Chirurgie viscérale Hôpitaux Universitaires de Genève Geneva Switzerland