1. Tumor Biology Center, Department of Medical Oncology, Clinical Research, Breisacher Strasse 117, 79106 Freiburg, Germany, Institute for Macromolecular Chemistry, Stefan-Meier-Strasse 31, 79104 Freiburg, Germany, and Klinge Pharma - Fujisawa Group, Weihenstephaner Strasse 28, 81673 Munich, Germany