1. Department of Clinical Pathology, Chengde Medical University, Chengde, Hebei 067000, P.R. China
2. Department of Pathology, Cangzhou People's Hospital, Cangzhou, Hebei 061000, P.R. China
3. Department of Thoracic Surgery, Cangzhou People's Hospital, Cangzhou, Hebei 061000, P.R. China