Prognostic significance of HIF-2α/EPAS1 expression in hepatocellular carcinoma

Abstract

To evaluate the prognostic significance of HIF-2alpha/EPAS1 expression in hepatocellular carcinoma (HCC). Surgical specimens from 315 patients with HCC as well as 196 adjacent noncancerous lesions and 22 cases of normal liver tissue were investigated by immunohistochemistry (IHC) for HIF-2alpha/EPAS1 using a standard detection system. Correlations with clinicopathological factors, VEGF, microvessel density (MVD), and prognosis were analyzed. Immunoreactivity of HIF-2alpha/EPAS1 was positive in 69.5% of HCC, 55.6% of adjacent noncancerous tissue, and 0% of normal liver tissue. And it was significantly correlated with tumor grade, venous invasion, intrahepatic metastasis, necrosis, and capsule infiltration. Correlation analysis of HIF-2alpha/EPAS1 with angiogenic factor VEGF (P<0.001), and MVD (P=0.016) was also noted. HIF-2alpha/EPAS1 protein was less frequently expressed in low MVD cases, whereas a high rate of expression was noted in cases with both medium and high MVD (P=0.042). By Kaplan-Meier analysis, strong HIF-2alpha/EPAS1 staining (>50% of tumor cells) in HCC correlated with a shortened survival in patients (Cox's regression, P<0.001, r=3.699). We conclude that HIF-2alpha/EPAS1 expression may play an important role in tumor progression and prognosis of HCC. Assessment of HIF-2alpha/EPAS1 expression in HCC may be used as a diagnostic tool and possibly a target in the treatment of HCC.