1. Chemische Biologie Universität Duisburg-Essen ZMB Fakultät für Biologie Universitätsstr. 2 45117 Essen Germany
2. Department of Dermatology University hospital Essen West German Cancer Center University Duisburg-Essen and the German Cancer Consortium (DKTK)
3. Current address: Division of Tumor Metabolism and Microenvironment German Cancer Research Center (DKFZ) Im Neuenheimer Feld 280 69120 Heidelberg Germany
4. Molekularbiologie I Universität Duisburg-Essen ZMB Fakultät für Biologie Universitätsstr. 2 45117 Essen Germany
5. Current address: University of Cologne Faculty of Medicine and University Hospital of Cologne Department of Gastroenterology and Hepatology Kerpener Str. 62 50937 Cologne Germany