1. Department of Endocrinology and Metabolism, Endocrine Tumour Center at West German Cancer Center, University Hospital Essen, University of Duisburg-Essen, Duisburg-Essen, Germany
2. Institute of Pathology, University Hospital Essen, University of Duisburg-Essen, Duisburg-Essen, Germany
3. German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany
4. Department of Radiotherapy, West German Cancer Center, University Hospital Essen, University of Duisburg-Essen, Duisburg-Essen, Germany