1. Department of Medical Oncology, The First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650000, P.R. China
2. Department of Oncology, The Affiliated Traditional Chinese Medical Hospital of Xinjiang Medical University, Urumqi, Xinjiang 830000, P.R. China
3. Department of Gastrointestinal Surgery, Xuzhou Hospital Affiliated to Medical School of Southeast University, Xuzhou, Jiangsu 221009, P.R. China