1. Princess Máxima Center for Pediatric Oncology, Heidelberglaan 24, 3584 CS Utrecht, The Netherlands
2. Department of Pathology, Radboud University Medical Center, Geert Grooteplein 1, 6500 HB Nijmegen, The Netherlands
3. Center for Medical Image Science and Visualization, Linköping University, 581 83 Linköping, Sweden
4. Department of Pathology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands