1. Department of Gastroenterology, The Sanming First Hospital Affiliated to Fujian Medical University, Sanming, Fujian 365000, P.R. China
2. BGI Education Center, University of Chinese Academy of Sciences, Beijing 100049, P.R. China
3. Department of Thyroid and Breast, Shanghai Tenth People's Hospital, Tongji University, School of Medicine, Shanghai 200072, P.R. China
4. Institute of Stem Cell Medicine, Fujian Medical University, Fuzhou, Fujian 350108, P.R. China