1. Department of Tumor Biology and Immunology, The Netherlands Cancer Institute, Amsterdam, The Netherlands;
2. Department of Immunohematology and Blood Transfusion, and
3. Oncode Institute, Leiden University Medical Center, Leiden, The Netherlands;
4. Willem Alexander Children’s Hospital/Leiden University Medical Center, Leiden, The Netherlands;
5. Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands;
6. Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA;
7. Division of Pathology, Cincinnati Children’s Hospital, Cincinnati, OH; and
8. Emma Children’s Hospital/Amsterdam UMC, Amsterdam, The Netherlands