This study was performed by Panqin Wang, Qingfeng Zhang, Shihua Li, Ben Cheng, Han Xue, Tian Shao, Zhenlong Wang, Ze-Xian Liu and Han Cheng

Panqin Wang, Shihua Li, Ben Cheng, Han Xue, Tian Shao, Zhenlong Wang and Han Cheng are from

College of Life Science, Zhengzhou University,

100 Science Avenue,

Zhengzhou 450000, P. R. China

Qingfeng Zhang and Ze-Xian Liu are from

Sun Yat-sen University Cancer Center,

Building 2#, 651 Dongfeng East Road,

Guangzhou 510060, P. R. China

Email: liuzx AT sysucc.org.cn

Tel/Fax: +86-20-87342025

Email: chenghan AT zzu.edu.cn

Tel/Fax: +86-0371-67780989