PURPOSE: Metabolic syndrome and insulin resistance have been linked to increased risk of occurrence and mortality of hepatocellular carcinoma (HCC). Recently, retinol-binding protein 4 (RBP4) was clarified as a specific serological marker of insulin resistance. The aim of this study was to determine whether serum RBP4 could be used as a potential marker for predicting prognosis in patients with HCC after curative resection.
METHODS: Western immunoblotting and Enzyme-linked immunosorbent assay were used to measure the RBP4 expression in cell lines, supernatant, and serum. Serum RBP4 levels were compared with clinicopathological features and outcomes of patients with HCC. Furthermore, we investigated the impact of serum RBP4 level, serum C-peptide level, and HOMA-IR on overall survival (OS) and disease-free survival (DFS) of patients with HCC in the training cohort (156 patients with HCC), and then were validated in the validation cohort (105 patients with HCC).
RESULTS: RBP4 protein overexpressed in HCC cell lines compared with normal liver cell line (P < 0.001) and correlated with metastatic potential. Serum RBP4 levels were associated with OS [hazard ratio (HR) = 2.208, P < 0.001] and DFS (HR = 1.878, P = 0.029) of patients with HCC. By multivariate analysis, the serum RBP4 level was identified as an independent factor for OS (HR = 2.170, P = 0.004) and DFS (HR = 1.769, P = 0.037) of patients with HCC. The prognostic value of serum RBP4 level was confirmed in the validation cohort.
CONCLUSIONS: The serum RBP4 level is potential to be a useful prognostic factor for HCC after curative resection.