Extracellular vesicle-associated epidermal growth factor receptor as a potential liquid biopsy biomarker in lung adenocarcinoma: a case-control study

Background: Extracellular vesicles (EVs) have recently emerged as potential noninvasive biomarkers for liquid biopsy because of the limitations of tissue biopsies in lung cancer. This study investigated the presence of EV-associated epidermal growth factor receptor (EGFR) in lung adenocarcinoma. Methods: EVs were collected from the serum samples of 32 patients with lung adenocarcinoma, 32 healthy controls, and conditioned culture media from A549 and BEAS-2B cell lines. EVs were isolated using ultracentrifugation and size-exclusion chromatography. Their characteristic features were confirmed by transmission electron microscopy, nanoparticle tracking analysis (NTA), and western blotting. Results: NTA revealed a two-fold increase in EV concentration in the serum of patients with lung cancer compared to healthy controls. Similarly, A549 cells secrete significantly more EVs than BEAS-2B cells. Western blotting validated the detection of canonical EV markers, such as TSG101, CD81, and flotillin-1, as well as the absence of calnexin. Notably, EGFR was highly packaged in the EVs isolated from both A549 cells and patient serum, whereas it was minimally present or absent in the EVs isolated from healthy controls and BEAS-2B cells. Conclusion: Our findings indicated that EGFR was selectively packaged into EVs derived from lung adenocarcinoma and was absent in non-cancerous controls. EV-associated EGFR could be a noninvasive indicator for the early detection of lung adenocarcinoma through liquid biopsy.