CD63 and hepatocellular carcinoma: Another exosomal marker CD63 was discovered as a kind of sialoglycoprotein, and the glycosylation of CD63 mediated by silencing α2,6-sialyltransferase I (ST6Gal-I) can alleviate the effects of HCC-derived EVs in promoting tumor progress, mainly through blocking the Akt/Glycogen synthase kinase (GSK)-3β or JNK1/2 pathways [46].