1 Children's Research Centre, Oncology, University Children's Hospital, August-Forel Strasse 1, CH-8008, Zürich, Switzerland.
2 Department of Oncology, University Children's Hospital Zürich, Steinwiesstrasse 75, CH-8032, Zürich, Switzerland.
3 Children's Research Centre, Oncology, University Children's Hospital, August-Forel Strasse 1, CH-8008, Zürich, Switzerland. Martin.Baumgartner@kispi.uzh.ch.