1. Department of Neurosurgery, Brigham and Women's Hospital and Children's Hospital, Harvard Medical School, Boston, Massachusetts
2. Department of Neurosurgery, Ankara University, School of Medicine, Sihhiye, Ankara, Turkey
3. Department of Radiation Oncology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
4. Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts