1. Department of General Surgery, Shanghai First People’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200080, China
2. Department of Anal-Colorectal Surgery, General Hospital of Ningxia Medical University, Yinchuan 750004, China
3. Department of Pathology, Shanghai First People’s Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200080, China