1. Department of Neurosurgery, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
2. Department of Neurosurgery, St. Vincent's Hospital, The Catholic University of Korea, Suwon, Korea.
3. Department of Pathology, Seoul St. Mary's Hospital, The Catholic University of Korea, Seoul, Korea.
4. Department of Hospital Pathology, Bucheon St.Mary's Hospital, The Catholic University of Korea, Bucheon, Korea.