1 Children's Cancer Research Center and Department of Pediatrics, Klinikum rechts der Isar, Technische Universitat München, München, Germany.
2 German Cancer Research Center (DKFZ), Partner Site Munich, München, Germany.
3 Institute of Pathology, School of Medicine, Technische Universitat München and Comparative Experimental Pathology (CEP), Technische Universitat München, München, Germany.
4 Department of Pediatrics, Division of Oncology and Hematology, Charite - Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin, Germany.
6 Department of Pediatrics, Division of Oncology and Hematology, Charite - Universitätsmedizin Berlin, Augustenburger Platz 1, Berlin, Germany. guenther.richter@charite.de.