D Schadendorf1, E Livingstone2, L Zimmer2. 1. Department of Dermatology, University Hospital Essen, West German Cancer Center, University Duisburg-Essen and the German Cancer Consortium (DKTK), Heidelberg, Germany. Electronic address: dirk.schadendorf@uk-essen.de. 2. Department of Dermatology, University Hospital Essen, West German Cancer Center, University Duisburg-Essen and the German Cancer Consortium (DKTK), Heidelberg, Germany.