The role of interleukin-17 (IL-17)-secreting CD4(+) T (Th17) cells in cancer is under intense investigation. We have demonstrated that CCR4(+)CCR6(+) Th17 cells not only are increased in the peripheral blood of patients affected by hepatocellular carcinoma, but also suppress CD8(+) T-cell functions in vitro. These results suggest that Th17 cells may exert immunosuppressive functions in hepatocellular carcinoma.