1. Department of Thoracic Surgery, West China Hospital of Sichuan University, Chengdu, Sichuan�610041, P.R.�China
2. The Key Laboratory of Molecular Biology for High Cancer Incidence Coastal Chaoshan Area, Shantou University Medical College, Shantou, Guangdong�515041, P.R.�China
3. Department of Oncology Surgery, Shantou Central Hospital, Affiliated Shantou Hospital of Sun Yat-Sen University, Shantou, Guangdong�515041, P.R.�China