EGFR and Pleural effusion: To monitor the tumor progression and effect of patient treatment, we collected pleural effusion samples at 7th, 8th, 13th, 15th, and 16th day and separated pleural effusion supernatant from pleural effusion pellet, and extracted psDNAs (pleural effusion supernatant DNAs) and ppDNAs (pleural effusion pellet DNAs) for ddPCR analysis (Figures 3C,D) on EGFR 858th and 790th sites.