The exosomes released by the transferred HCC cells in turn carried a large amount of tumorigenic RNAs and proteins, enhanced the phosphorylation of PI3K/AKT and MAPK pathways and the production of matrix metalloproteinase (MMP)-2 and MMP-9, which promoted the migration and invasion capacity of MIHA cells [81]. The gene discussed is MMP9; the disease is hepatocellular carcinoma.