1. Division of Neurology, First Department of Internal Medicine; Asahikawa Medical University; Asahikawa Japan
2. Department of Neurosurgery; Asahikawa Medical University; Asahikawa Japan
3. Department of Clinical Pathology; Asahikawa Medical University; Asahikawa Japan
4. Department of Translational Pathology; Hokkaido University School of Medicine; Sapporo Japan