Proteoglycans are a heterogeneous family of macromolecules that consist of a core protein and one or more covalently attached polysaccharide‐chains.[126] For instance, CD44, a hyaluronic acid binding glycoprotein, was found to be enriched on the surface of EVs derived from cancer cells and, subsequent to EV uptake, EVs induced a change in cellular morphology of human peritoneal mesothelial cells. Here, CD44 is linked to cancer.