1. Department of Medical Oncology, West German Cancer Center, University Hospital Essen
2. Institute of Pathology Essen, West German Cancer Center, University Hospital Essen, Germany
3. Department of General, Visceral and Transplant Surgery, West German Cancer Center, University Hospital Essen, Essen, Germany
4. Department of General Surgery and Traumatology, Elisabeth Hospital, Essen, Germany
5. Department of Gastroenterology, Hepatology and Transplantation Medicine University Hospital Essen, Germany
6. Department of Gastroenterology, Elisabeth Hospital, Essen, Germany
7. Institute of Pathology Nordhessen, Kassel, Germany