Targeting Oncofoetal Chondroitin Sulphate Allows Identification of Tumour-Derived Extracellular Vesicles

Tumour-derived extracellular vesicles (tdEVs) are widely studied for their contribution to tumour progression and metastasis. These studies are hampered by the lack of specific markers to identify the tdEVs. Here, we show that oncofoetal chondroitin sulphate, a malignancy-associated glycosaminoglycan modification, is present on tdEVs and can be targeted by the malaria VAR2CSA protein or C9 antibody. Using a fluorescently labelled recombinant VAR2CSA protein, we identified EVs from cancer cells in vitro by super-resolution fluorescence microscopy and flow cytometry, as well as in a proof-of-concept study using plasma samples from pancreatic adenocarcinoma patients. Thus, the binding of VAR2CSA offers a tool to identify tdEVs, and can be used to explore their function and biomarker potential in cancer.