1. Department of Gastroenterology, The Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, China;
2. Department of Thoracic Surgery, The Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, China;
3. Department of Pathology, The Second Affiliated Hospital of Xi’an Jiaotong University, Xi’an, Shaanxi, China