Expression of Ribosomal Protein S23 in Hepatocellular Carcinoma Tissue as Good Prognostic Marker

Background: Ribosomal proteins (RP) involve in the regulation of apoptosis and carcinogenesis. In recent studies of RP in hepatocellular carcinoma (HCC), the overexpression of ribosomal protein L12, L27, L30 and L36 was found. We aimed to investigate the expression of ribosomal protein S23 (RPS23) and its effect on prognosis in postoperative HCC patients. Methods: Liver tissues were obtained 63 patients who had undergone curative resection for HCC. We enrolled the patients with early tumor stage (≤ UICC stage III) and good liver function (≤ Child Pugh score 6). The expressions of RPS23 in tumor tissue and non-tumor tissue were examined by immunohistochemical staining. Analyses for survival and recurrence were done between tumor RPS23 (t-RPS23) expression group and non-expression group. Results: RPS23 was expressed in 34 patients (54.0%) on tumor tissue and 8 patients (13.1%) in Non-tumor tissues (P=0.016). The patients were grouped according to the expression of RPS26 in tumor tissue. Basal characteristics were not different between t-RPS23 positive and negative group. The three years and five years survival rate was higher in t-RPS23 positive group (90.2% vs. 65.8% of 3 year survival rate, P=0.007, 86.1% vs. 55.7% of 5 year survival rate, P=0.010). On multivariate analysis, t-RPS23 expression (HR 10.95, P=0.004) and tumor number (HR 9.71, P=0.001) were independent prognostic factors for 3 year and 5 year survival. Tumor recurrence during one year after resection was relatively low in t-RPS23 positive group, but not statistically significant (17.8% vs. 36.0%, P=0.084). However, on multivariate analysis, t-RPS23 expression (HR 4.18, P=0.021) and serosa invasion (HR 4.15, P=0.019) were independent factors for 1 year tumor recurrence. Conclusions: The RPS23 expression of HCC patients was higher in tumor tissue than in non- tumor tissues. The RPS23 expression in tumor tissue was good prognostic marker for resected HCC. RPS23 may be associated with good oncogene to have paradoxical function in HCC.