The clinical investigation data showed that both of the MG53 mRNA and protein levels were significantly downregulated in HCC tissues compared with non-cancerous liver tissues, and the levels of MG53 and RAC1 was significantly negatively correlated, which indicated that the negative regulation of RAC1 might be involved in the progression of hepatocarcinogenesis. The gene discussed is RAC1; the disease is hepatocellular carcinoma.