1. State Key Laboratory of Cancer Biology and Department of Physiology and Pathophysiology Fourth Military Medical University Xi'an Shaanxi 710032 P. R. China
2. Department of General Surgery Tangdu Hospital Fourth Military Medical University Xi'an Shaanxi 710032 P. R. China
3. Department of Hepatobiliary Surgery Xijing Hospital Fourth Military Medical University Xi'an Shaanxi 710032 P. R. China
4. Department of Respiratory Medicine Xijing Hospital Fourth Military Medical University Xi'an Shaanxi 710032 P. R. China