1. Laboratory of Radiobiology and Experimental Radiooncology, Center of Oncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
2. Tumor Biology Department, National Cancer Institute, Cairo University, Cairo, Egypt
3. Department of Radiotherapy and Radiooncology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
4. Department of Pathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
5. Department of Otorhinolaryngology and Head and Neck Surgery, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
6. Department of Radiation Oncology, Ludwig Maximilians University, Munich, Germany
7. Clinical Cooperation Group ‘Personalized Radiotherapy of Head and Neck Cancer’, Helmholtz Center Munich, Neuherberg, Germany