1. Department of Neurosurgery, Keio University School of Medicine, Shinanomachi, Shinjuku-ku, Tokyo, Japan
2. Department of Neurosurgery, Jikei University Kashiwa Hospital, Kashiwashita, Kashiwa-shi, Chiba, Japan
3. Department of Neurosurgery, Kagawa University Hospital, Ikedo, Mituki-cho, Kita-gun, Kagawa, Japan
4. Department of Neurosurgery, Japan Red Cross Medical Center, Hiroo, Shibuya-ku, Tokyo, Japan
5. Division of Diagnostic Pathology, Keio University School of Medicine, Shinanomachi, Shinjuku-ku, Tokyo, Japan
6. Division of Gene Regulation, Institute for Advanced Medical Research, Keio University School of Medicine, Shinanomachi, Shinjuku-ku, Tokyo, Japan
7. Department of Neurosurgery, Jikei University Hospital, Nishishinbashi, Minato-ku, Tokyo, Japan