Fig. 1.
Flow chart of signature identification and validation strategy. Abbreviations: BJ cohort, patients from Peking University People’s Hospital; CQ cohort, patients from Southwest Hospital of Chongqing; ADC, adenocarcinoma; SCC, squamous cell carcinoma; IHC, immunohistochemistry; EGFR-TKI, epidermal growth factor receptor tyrosine kinase inhibitor