AIM: To study the biological and clinical characteristics of transcription factor forkhead box protein 3 (FOXP3) in hepatocellular carcinoma (HCC). METHODS: We analyzed the expression and localization of FOXP3 in HCC tissues and cell lines to evaluate its biological features. The relationship between FOXP3 staining and clinical risk factors of HCC was assessedto identify the clinical characteristics of FOXP3 in HCC. RESULTS: The mRNA and protein expression of FOXP3 were found in some hepatoma cell lines. Immunohistochemical (IHC) analysis of HCC sections revealed that 48% of HCC displayed FOXP3 staining, but we did not find any FOXP3 staining in normal liver tissues and para-tumor tissues. IHC and Confocal analysis showed that the expressions of FOXP3 were mainly present in the nucleus and cytoplasm of tumor cells in tissues or cell lines. In HCC, the distribution of FOXP3 was similar to that of the cirrhosis, but not to the hepatitis B virus. Those findings implicate that FOXP3 staining seems to be associated with the high risk of HCC. CONCLUSION: The clinical characteristics of FOXP3 in HCC warrants further studies to explore its functions and roles in the cirrhosis and development of HCC. AIM: To study the biological and clinical characteristics of transcription factor forkhead box protein 3 (FOXP3) in hepatocellular carcinoma (HCC). METHODS: We analyzed the expression and localization of FOXP3 in HCC tissues and cell lines to evaluate its biological features. The relationship Between FOXP3 staining and clinical risk factors of HCC was assessed to identify the clinical characteristics of FOXP3 in HCC. RESULTS: The mRNA and protein expression of FOXP3 were found in some hepatoma cell lines. Immunohistochemical (IHC) analysis of HCC sections revealed that 48% of HCC displayed FOXP3 staining, but we did not find any FOXP3 staining in normal liver tissues and para-tumor tissues. IHC and Confocal analysis showed that the expressions of FOXP3 were mainly present in the nucleus and cytoplasm of tumor cells in tissues or cell lines. In HCC, the distribution of FOXP3 was similar to that of the cirrhosis, but not to hepatitis B virus. Those findings implicate that FOXP3 staini CONCLUSION: The clinical characteristics of FOXP3 in HCC warrants further studies to explore its functions and roles in the cirrhosis and development of HCC.