1. Department of Pathology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
2. Department of Endoscopy, Sun Yat‑sen University Cancer Center, Guangzhou, Guangdong 510060, P.R. China
3. Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou Medical University, Guangzhou, Guangdong 510095, P.R. China