CD24 Is a Novel Predictor for Poor Prognosis of Hepatocellular Carcinoma after Surgery

Purpose: To investigate the role of CD24 in tumor invasion and prognostic significance in hepatocellular carcinoma (HCC). Experimental Design: CD24 expression was measured in stepwise metastatic HCC cell lines, tumor, peritumoral tissues, and normal liver tissues by quantitative real-time PCR and Western blot. The role of CD24 in HCC was investigated by CD24 depletion using small interfering RNA. Tumor tissue microarrays of 314 HCC patients who underwent resection between 1997 and 2000 were used to detect expression of CD24, P-catenin, and proliferating cell nuclear antigen. Prognostic significance was assessed using Kaplan-Meier survival estimates and log-rank tests. Results: CD24 was overexpressed in the highly metastatic HCC cell line and in tumor tissues of patients with recurrent HCC. Depletion of CD24 caused a notable decrease in cell proliferation, migration, and invasiveness in vitro. Univariate and multivariate analyses revealed that CD24 was a significant predictor for overall survival and relapse-free survival. CD24 expression was correlated with poor prognosis independent of a-fetoprotein, tumor-node-metastasis stage, and Edmondson stage. High CD24 expression was significantly associated with cytoplasmic and nuclear accumulation of beta-catenin (P = 0.023), high tumor proliferative status (P = 0.018), and diffused intrahepatic recurrence and distant metastasis (P = 0.026). Adjuvant transcatheter arterial chemoembolization after surgery reduced the rate of early recurrence (<= 1 year) in CD24(+) HCC patients (P = 0.024) but had no significant effect in CD24(-) patients (P = 0.284). Conclusions: Overexpression of CD24 in HCC was associated with high invasiveness and metastatic potential, high tumor proliferation status, and activation of the Wnt/beta-catenin pathway. CD24 may be a novel predictor for poor prognosis of HCC patients after surgery. (Clin Cancer Res 2009;15(17):5518-27)