Fig. 1

a EV repertoire. Cells secrete distinct sub-populations of EVs and although of different origins, they overlap in size or density and often co-purify. Exosomes are vesicles generated by the inward budding of the endosomal compartments (endocytic vesicles), which become early endosomes (EE), several of which are forming so-called multivesicular bodies (MVBs). MVBs either fuse with lysosomes or with the plasma membrane, which results in their secretion. In addition, cancer cells can produce larger vesicles named “large oncosomes”. Together with exosomes and microvesicles, oncosomes contain abundant bioactive molecules, which can transfer cancer traits or be used as biomarkers. b Relative to the general EV content of normal cells (tetraspanins, MHC molecules, proteins involved in the MVB biogenesis, heat shock proteins), cancer EVs are often enriched in specific miRNAs or proteins. Furthermore, the membrane of cancer EVs is characterised by specific lipid species localised in lipid rafts. c Cancer cells secrete more EVs than the corresponding healthy cells. Acidic pH and hypoxia, which often characterise the tumor microenvironment, stimulate an increased secretion of EVs and influence the EV content, which in turn supports angiogenesis and metastasis. Additional references not previsouly cited in the text: KRAS [99], Annexin A3 [100], TGFβ [101], Glypican 1 [102]