Correspondence to: Jian-Kun Hu, PhD, MD, Professor, Department of Gastrointestinal Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Xiang, Chengdu 610041, Sichuan Province, China. hujkwch@ 126.com Telephone: +86-28-85422878 Fax: +86-28-85164035