MMP9 and hepatocellular carcinoma: Similarly, in hepatocellular carcinoma (HCC), miR-21 derived from the tumor reduces PTEN levels, leading to the activation of the PDK1/AKT signaling pathway and an increase in the expression of VEGF, MMP2, MMP9, βFGF, and TGF-β in CAFs, thereby promoting angiogenesis [152, 153].