 The study was designed as a prospective and single center study. Seventy patients will be enrolled into the study and the clinical data of the patients, including his smoke history, cancer history, occupation exposure and so on, will be collected and recorded in a case report form. For the patients recruited in the study, the lymph nodes suspected to be malignant will be obtained by EBUS-TBNA. Samples will be sent to Pathology Department of Shanghai Chest Hospital and will be processed with paraffin-embedded, and for those diagnosed with nonsquamous NSCLC, routine gene testing of EGFR, ROS1 and ALK will be performed. And the rest tissues will be extracted with DNA and performed gene mutations using NGS for these qualified DNA samples. 