Min Tang1, Bin Ai1, Li Ding1, Jun Du2, Gang Cheng1, Yongqiang Zhang3. 1. Department of Oncology, Beijing Hospital of the Ministry of Health, Beijing 100730, China. 2. Department of Pathology, Beijing Hospital of the Ministry of Health, Beijing 100730, China. 3. Department of Oncology, Beijing Hospital of the Ministry of Health, Beijing 100730, China. Email: zhyq95@163.com.