Current studies have shown that samples collected from lung cancer patients, including blood plasma, pleural effusion, and bronchoalveolar lavage fluid (BALF), contain EV-DNA with detectable epidermal growth factor receptor (EGFR) mutations (e.g., exon 19 deletion, p.L858R, p.T790M) (Table 1) [38, 123, 124, 126, 127]. This evidence concerns the gene EGFR and Pleural effusion.