Oncoproteins are abundant in the exosomes produced by metastatic HCC cells, such as MET protooncogene, S100 family members and the caveolins, which activate PI3K/AKT and MAPK signaling pathways in normal hepatocytes after absorbing them, resulting in upregulation of MMP2 and MMP9 and such enhancing tumor cells migration and invasion (148). Here, MMP2 is linked to hepatocellular carcinoma.