1. Department of Neurosurgery, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea.
2. Department of Pathology, National Cancer Center, Goyang, Korea.
3. Department of Neurological Surgery, Asan Hospital, University of Ulsan College of Medicine, Seoul, Korea.
4. Department of Cancer Control, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang, Korea.