1. Department of Respiration, Penglai Traditional Chinese Medicine Hospital, Yantai, Shandong 265600, P.R. China
2. Department of Surgery, Penglai People's Hospital, Yantai, Shandong 265600, P.R. China
3. Department of Oncology, Baiyin Central Hospital, Baiyin, Gansu 730913, P.R. China