1 Department of Gastroenterology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China.
2 Department of Oncology, Weifang People's Hospital (The First Affiliated Hospital of Weifang Medical University), Weifang, Shandong, China.
3 Department of Gastroenterology, West China School of Public Health, West China Forth Hospital, Non-communicable Diseases Research Center, West China-PUMC C.C. Chen Institute of Health, Sichuan University, Chengdu, China.
4 Department of Gastroenterology, The First Affiliated Hospital of Xi 'an Jiaotong University, Xi an, China.
5 Department of Gastroenterology, The Second Affiliated Hospital of Baotou Medical College, Inner Mongolia University of Science and Technology, Inner Mongolia Institute of Digestive Diseases, Baotou, China.
6 Department of Gastroenterology, Affiliated Hospital of Inner Mongolia Medical University, Hohhot, China.
7 Department of Surgical Science, Cagliari State University, Cagliari, Italy.