1. Department of Thoracic Surgery and Endoscopy, Ruhrlandklinik, University of Duisburg-Essen, Essen, Germany
2. Department of Medical Oncology, West German Cancer Center, University of Duisburg-Essen, Essen, Germany
3. Institut of Pathology and Neuropathology, University of Duisburg-Essen, Essen, Germany