1. From the Departments of Thoracic Surgery (Drs Wang, Zhang, and Liu; Messrs Liang and Feng; and Ms Guo) and Pathology (Mss Wang and Da), China-Japan Friendship Hospital, Beijing, China; the National Institute of Metrology, Beijing (Mr Gao); Beijing ACCB Biotech Ltd, Beijing (Drs Mo, Ding, Chen, and Li and Mr Zhang); and the Department of Biotechnology and Pharmaceutical Research, Yangze Delta Inst