1. Department of Neurosurgery, Kaohsiung Veterans General Hospital, Kaohsiung 807, Taiwan
2. Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
3. National Institute of Cancer Research, National Health Research Institutes, Tainan 701, Taiwan
4. Division of Neurosurgery, Department of Surgery, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
5. Department of Pathology, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan
6. Department of Pathology, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
7. Department of Surgery, School of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan
8. Department of Neurosurgery, University of Virginia, Charlottesville, VA 23806, USA