1. Department of Urology, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
2. Department of Biochemistry, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
3. Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
4. Department of Pharmacology, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
5. Department of Oncology, Internal Medicine, University of California, Davis, CA 95817, USA