1. Department of General and Visceral Surgery, University Medical Center Goettingen, Goettingen, Germany
2. Department of Medical Statistics, University Medical Center Goettingen, Goettingen, Germany
3. Division of Epigenomics and Cancer Risk Factors, German Cancer Research Center (DKFZ), Heidelberg, Germany
4. Dept. of Medicine, Div. Hematology/Oncology, University of Freiburg Medical Center, Freiburg, Germany (present address)
5. Department of Pathology, University Medical Center Goettingen, Goettingen, Germany
6. Department of Radiation Oncology, University Medical Center Goettingen, Goettingen, Germany
7. Radiotherapy Department, Cyclotron Biomédical, Centre Antoine-Lacassagne Nice, France