1. Department of Pathology, Affiliated Hospital of Chengde Medical College, Chengde, Hebei 067000, P.R. China
2. Department of Tumor Radiation and Chemotherapy Center, Chengde Central Hospital, Chengde, Hebei 067000, P.R. China
3. Department of General Surgery IV, Baoding First Hospital, Baoding, Hebei 071000, P.R. China