**Acknowledgements**

Disclosures: JTT, BASJ, AU, PG, VG, and LK have nothing to disclose.

MS has received research funding and lecture honoraria from Novartis Pharmaceuticals (Nürnberg, Germany), Bristol-Myers Squibb (Munich, Germany), and Pfizer (Berlin, Germany).

Funding: Continuous financial support was provided by unrestricted research grants from Novartis Pharmaceuticals (Nürnberg, Germany), Sonnenstrahl e. V. (Dresden, Germany), and Stiftung Mitteldeutsche Kinderkrebsforschung (Leipzig, Germany). Additional financial support was given by a research grant from the Deutsche Forschungsgemeinschaft (#SU122/3-1; Bonn, Germany).
