Expression and clinical significance of ABCG2 protein in hepatocellular carcinoma

Abstract

Objective To investigate the expression and clinical significance of ABCG2 protein in hepato-cellular carcinoma (HCC). Methods Specimens of HCC were collected at The First Aifiliated Hospital of Sun Yat-sen University from January 2005 to December 2006. The expression of ABCG2 protein in 165 samples of HCC tissue, 25 samples of normal liver tissue and 40 samples of cirrhotic liver tissue was detected using immunohisto-chemistry. The correlation between the expression of ABCG2 protein and clinicopathological characters was then analyzed. Enumeration data, survival rate and the difference between groups were analyzed with a chi-square test, the Kaplan-Meier method and Log-rank test, respectively. Results ABCG2 protein expression was weakly posi-tive in all normal and cirrhotic liver tissues. In HCC tissues, the expression of ABCG2 protein was strongly positive in 66 cases and weakly positive in 99 cases. The expression of ABCG2 protein was related to tumor diameter, tumor number, adjacent organ invasion and TNM stages (χ2 =8. 130, 14. 279, 4. 820, 21. 179, P <0. 05). Kaplan-Meier survival analysis revealed that patients with strongly positive ABCG2 protein had a significantly lower 3-year overall survival (24. 1%) compared with those with weakly positive ABCG2 protein (39. 4%) (χ2 = 15.716, P<0.05). Conclusions The expression level of ABCG2 protein is related to tumor invasiveness, TNM stage and prognosis. ABCG2 has the potential to become a new target for HCC treatment. Key words: Liver neoplasms; ABCG2 protein; Prognosis