Zhou et al. found that miR-21 in HCC exosomes could activate HSCs and promote the transformation of HSCs to CAFs by regulating the PTEN/PDK1/Akt pathway, and these CAFs are closer to newborn blood vessels than other cells, suggesting that miR-21-activated CAFs may promote HCC progression by participating in angiogenesis [14]. The gene discussed is PTEN; the disease is hepatocellular carcinoma.