Liquid biopsy, more specifically EVs, could contribute to improved cancer progression and therapy follow-up, as EVs containing EGFR DNA, RNA or protein were detected in blood, cerebrospinal fluid, bronchoalveolar lavage or pleural effusions in different cancers (Table 1), which in some studies correlated with prognosis (Skog et al., 2008; Shao et al., 2012; Yamashita et al., 2013; Figueroa et al., 2017; Lee J. S. et al., 2018; Castellanos-Rizaldos et al., 2018; Krug et al., 2018; Wan et al., 2018; Ortega et al., 2019; Qu et al., 2019; Song et al., 2019). This evidence concerns the gene EGFR and Pleural effusion.