High Expression of Retinoblastoma-Binding Protein 2 (RBP2) in Patients with Hepatocellular Carcinoma and Its Prognostic Significance

BACKGROUND Recently, some studies have found that retinoblastoma-binding protein 2 (RBP2) is involved in the development and progression of many kinds of malignant tumors. This study aimed to explore the expression level of RBP2 in hepatocellular carcinoma (HCC) and its prognostic significance. MATERIAL AND METHODS Immunohistochemical analysis was used to evaluate the RBP2 expression level in 130 HCC patients and adjacent normal tissues. Tumor angiogenesis was marked by CD31 and vascular endothelial growth factor (VEGF) staining. Kaplan-Meier and Cox regression analyses were performed to examine the relationship between RBP2 expression and prognosis of HCC patients. RESULTS RBP2 expression was significantly higher in HCC tissues (positive expression rate: 72.3%, 94/130). Increased RBP2 expression was dramatically associated with AFP level (P=0.016), degree of differentiation (P=0.000), and TNM stage (P=0.035). Moreover, tumors with RBP2-positive expression showed significantly higher intratumoral MVD than those with RBP2-negative expression (P=0.000). Kaplan-Meier analysis revealed RBP2-positive expression was related to decreased disease-free survival (DFS) (P=0.000) and overall survival (OS) (P=0.000). Furthermore, RBP2 was an independent poor prognostic factor of DFS and OS (P=0.029 and 0.010, respectively) as demonstrated by multivariate analysis. CONCLUSIONS Increased RBP2 expression, as an independent poor prognostic factor for DFS and OS of HCC patients, is closely related to tumor angiogenesis. RBP2 is expected to become a new potential therapeutic target for HCC.