1. Department of Dermatology, Venerology and Allergology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
2. West German Cancer Center, University Duisburg-Essen, Essen, Germany
3. German Cancer Consortium (DKTK), Heidelberg, Germany
4. Center for Psychosocial Medicine, Institute of Health Care Research in Dermatology and Nursing (IVDP), University Hamburg, Hamburg, Germany