1. 1Institute of Medical Research, Northwestern Polytechnical University, Xi'an, Shaanxi, P.R. China.
2. 2State Key Laboratory of Holistic Integrative Management of Gastrointestinal Cancers and Department of Physiology and Pathophysiology, Fourth Military Medical University, Xi'an, Shaanxi, P.R. China.
3. 3Department of General Surgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, P.R. China.
4. 4Department of General Surgery, the 71st Group Army Hospital of the People's Liberation Army, Xuzhou, Jiangsu, P.R. China.
5. 5Department of Urology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, P.R. China.