Extracellular Vesicles as a Novel Liquid Biopsy-Based Diagnosis for the Central Nervous System, Head and Neck, Lung, and Gastrointestinal Cancers: Current and Future Perspectives

Early diagnosis, along with innovative treatment options, are crucial to increase the overallsurvival of cancer patients. In the last decade, extracellular vesicles (EVs) have gained great interestin biomarker discovery. EVs are bilayer lipid membrane limited structures, released by almost allcell types, including cancer cells. The EV cargo, which consists of RNAs, proteins, DNA, and lipids,directly mirrors the cells of origin. EVs can be recovered from several body fluids, including blood,cerebral spinal fluid (CSF), saliva, and Broncho-Alveolar Lavage Fluid (BALF), by non-invasive orminimally invasive approaches, and are therefore proposed as feasible cancer diagnostic tools. Inthis review, methodologies for EV isolation and characterization and their impact as diagnostics forthe central nervous system, head and neck, lung, and gastrointestinal cancers are outlined. For eachof these tumours, recent data on the potential clinical applications of the EV’s unique cargo, alone orin combination with currently available tumour biomarkers, have been deeply discussed.