A recent study has indicated that the percentages of CD4+CD25+FOXP3+Treg cells and CD4+IL-17+Th17 cells were significantly higher in HCC patients than in the healthy individuals; Moreover, the increased percentages of Treg and Th17 cells were closely related to the tumor stage and tumor size of HCC [11]. The gene discussed is CD4; the disease is hepatocellular carcinoma.