Retinoic acid receptor-related receptor alpha (RORalpha) is a prognostic marker for hepatocellular carcinoma.

ABSTRACT

Retinoic acid receptor-related receptor alpha (RORalpha) has been proven to play a tumor suppressive role in certain types of solid tumors. However, the clinical characteristic of RORalpha has not been reported by far. This study investigated the expression of RORalpha in hepatocellular carcinoma (HCC) and evaluated its relationship with clinical parameters and prognosis in HCC patients. Quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) and Western blot analyses were performed to detect RORalpha expression levels in 20 paired HCC and corresponding adjacent non-cancerous tissues. Immunohistochemistry was performed on 100 archived paraffin-embedded HCC samples. Statistical analyses evaluated the correlations between RORalpha expression and clinicopathological features. qRT-PCR showed that RORalpha mRNA expression was significantly down-regulated in tumors compared to the adjacent non-cancerous tissues, and Western blots found that RORalpha protein expression was also reduced in tumor tissues. Immunohistochemical assays revealed that decreased RORalpha expression was present in 65 % of HCC patients. Correlation analyses showed that RORalpha expression was significantly correlated with serum alpha fetoprotein (AFP, p = 0.005), pathology grade (p < 0.001), tumor recurrence (p = 0.008), and vascular invasion (p < 0.001). Kaplan-Meier analysis revealed that patients with low RORalpha expression levels had a shorter overall and disease-free survival than patients with high expression (p < 0.001 and p = 0.002, respectively). Multivariate regression analysis indicated that RORalpha was an independent predictor for overall survival and disease-free survival. In conclusion, the results of our study showed that down-regulated RORalpha expression was associated with poorer prognosis in HCC patients. RORalpha may be a new potential prognostic marker for HCC patients.