1. Department of Oncology; Zhongshan Hospital, Fudan University; Shanghai 200032 P. R. China
2. Department of Clinical Oncology; The First Affiliated Hospital, Zhengzhou University; Zhengzhou 450052 Henan P. R. China
3. Department of Medical Oncology; Fudan University Shanghai Cancer Center; Shanghai 200032 P. R. China
4. Department of Oncology; Tongji University Eastern Hospital; Shanghai 200120 P. R. China
5. Department of Medical Oncology; Sun Yat-Sen University Cancer Center; Guangzhou 510060 Guangdong P. R. China
6. Department of Oncology; 307th Hospital of PLA, Academy of Military Medical Sciences; Beijing 100071 P. R. China
7. Department of Medical Oncology; Affiliated Cancer Hospital of Zhengzhou University, Henan Cancer Hospital; Zhengzhou 450008 Henan P. R. China
8. Department of Oncology; People's Liberation Army (PLA) Cancer Center, 81st Hospital of PLA; Nanjing 210002 Jiangsu P. R. China
9. Medical Department; Harbin Medical University Cancer Hospital; Harbin 150081 Heilongjiang P. R. China
10. Department of Oncology; First People's Hospital of Changzhou; Changzhou 213003 Jiangsu P. R. China
11. Roche (China) Holding Co., Ltd.; Shanghai 201203 P. R. China
12. Medical Division; Shanghai Roche Pharmaceuticals Ltd.; Shanghai 201203 P. R. China
13. Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Gastrointestinal Oncology; Peking University Cancer Hospital and Institute; #52 Fucheng Road, Haidian District Beijing 100142 P. R. China