1. Department of NeurosurgeryUniversity of Wuerzburg97080WuerzburgGermany
2. Department of NeuropathologyUniversity of BonnBonnGermany
3. Laboratory of Neuro‐OncologyDepartment of Veterans Affairs Medical CenterWashingtonDCUSA
4. University of South Dakota School of MedicineVermillionSouth DakotaUSA
5. Department of PathologyChildren's National Medical CenterWashingtonDCUSA