1. Department of Oncology, The Affiliated Hospital of Qingdao University, Qingdao, Shandong 266000, P.R. China
2. Department of Pathology, The Affiliated Hospital of Qingdao University; Qingdao, Shandong 266000, P.R. China
3. Department of Medical Oncology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, P.R. China