Assets of Circulating Extracellular Vesicles for Early Diagnosis and Prognosis of Gastric Cancer by Liquid Biopsy

Gastric cancer (GC) is an important human cancer, which needs new biomarkers for early diagnosis in order to improve the patients outcome. The aim of this review is to stress the huge interest of extracellular vesicles circulating into blood and other body fluids, as potential candidates for early diagnosis of gastric cancer. After briefly recalling the previous blood-based liquid biopsies as a non-invasive help to GC diagnosis and the main properties of extracellular vesicles, the review will be focused on the recent progressive emergence of exosomes as important partners in GC liquid biopsy. Faced with the always increasing number of exosomal biomarker candidates, the necessity of two independent searches is suggested. The biologists need to solve some pending biological problems about extracellular vesicles, and the eukaryotic microorganism Dictyostelium discoideum might be an appealing both "in vitro and in vivo" model for that purpose. On the other hand, the protocols for isolation and characterization of extracellular vesicles and their cargoes have to be strictly standardized for a further validation at a large scale, prerequisite for an efficient clinical translation of some promising biomarker (s) for gastric cancer diagnosis and prognosis.