1. Thoracic Medicine Department 1, Hunan Cancer Hospital Affiliated to Xiangya Medical School, Central South University, Changsha, Hunan 410013, P.R. China
2. Hematology Department, Hunan Cancer Hospital Affiliated to Xiangya Medical School, Central South University, Changsha, Hunan 410013, P.R. China
3. Department of Geriatrics, Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China