1. State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou, Guangdong, China
2. Collaborative Innovation Center of Cancer Medicine, Guangzhou, Guangdong, China
3. Department of Colorectal Surgery, Cancer Center, Sun Yat-sen University, 651 Dongfeng Road East, Guangzhou, Guangdong 510060, P. R. China