We found that miRNA-21 is associated with greater activation of cancer-associated fibroblasts (CAFs) and higher blood vessel density in HCC patients, as HCC cells secrete exosomes miRNA-21 that directly targets PTEN, resulting in hepatic stellate cells (HSCs) Activation of PDK1/AKT signaling pathway. The gene discussed is PDK1; the disease is hepatocellular carcinoma.