1. Department of General Surgery and Center of Minimal Invasive Gastrointestinal Surgery, Southwest Hospital, Third Military Medical University, and Key Laboratory of Tumor Immunopathology of Ministry of Education of China, Chongqing 400038, P.R. China
2. Institute of Pathology and Southwest Cancer Center, Southwest Hospital, Third Military Medical University, and Key Laboratory of Tumor Immunopathology of Ministry of Education of China, Chongqing 400038, P.R. China