1. Department of General Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
2. The Vivian L. Smith Department of Neurosurgery, the University of Texas Medical School at Houston, Houston, Texas, USA
3. Department of Pathology and Pathophysiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
4. Department of Pathology and Pathophysiology, School of Basic Medical Sciences, Capital Medical University, Beijing, China