CD4 and hepatocellular carcinoma: As shown in Fig. 2A, the proportion of CD4+CD25+FOXP3+ Treg cells was significantly higher in the different HCC tumor stage groups than in the control group; moreover, the proportion of CD4+CD25+FOXP3+ Treg cells was significantly higher in the advanced (stage III-IV) HCC group than in the early (stage I–II) HCC group.