1. Cancer Drug Development Group German Cancer Research Center (DKFZ) Im Neuenheimer Feld 280 69120 Heidelberg Germany
2. Faculty of Biosciences University of Heidelberg 69120 Heidelberg Germany
3. Chemical Biology Core Facility European Molecular Biology Laboratory (EMBL) 69117 Heidelberg Germany
4. Hopp Children's Cancer Center Heidelberg (KiTZ) 69120 Heidelberg Germany
5. Clinical Cooperation Unit Pediatric Oncology German Cancer Research Center (DKFZ) 69120 Heidelberg Germany
6. Department of Pediatric Oncology Hematology and Immunology University Hospital Heidelberg 69120 Heidelberg Germany
7. German Cancer Consortium (DKTK) 69120 Heidelberg Germany
8. Roy and Diana Vagelos Laboratories Department of Chemistry University of Pennsylvania Philadelphia PA 19104-6323 USA