Li et al. found that exosomes containing CXC chemokine receptor-4 (CXCR4) produced by high-mobility HCC can stimulate and promote migration and invasion of low-metastatic HCC cells in distant or surrounding region, which may be due to the fact that exosomal CXCR4 can mediate the secretion of MMP-2/9 in the ECM [170]. The gene discussed is CXCR4; the disease is hepatocellular carcinoma.