1. Department of Radiation Oncology, Affiliated Hospital of Guilin Medical University, Guilin 541001, P.R. China
2. Department of Oncology, Xianning Central Hospital, The First Affiliated Hospital of Hubei University of Science and Technology, Xianning 437100, P.R. China
3. Department of Pathology, The 181st Hospital of People's Liberation Army, Guilin 541001, P.R. China