RING-finger protein 5 promotes hepatocellular carcinoma progression and predicts poor prognosis

Hepatocellular carcinoma (HCC) is one of the most common cause of malignancy-related deaths. Recently, RING-finger protein 5 (RNF5), an E3 ubiquitin ligase, was revealed to be associated with the development of several human cancers. However, the clinical implication and functional role of RNF5 in HCC are poorly understood. We analysed RNF5 expression in HCC samples and observed that both the mRNA and protein levels of RNF5 were significantly increased in HCC tissues. RNF5 upregulation was markedly associated with larger tumour size, more satellite foci, and higher alpha fetoprotein (AFP) level, indicating poor prognosis in patients with HCC. Knockdown and overexpression experiments demonstrated that RNF5 promoted the proliferation, migration, and invasion of HCC cells in vitro. Moreover, RNF5 facilitated HCC growth in vivo. Our findings indicated that RNF5 was an oncogene of HCC progression and could be used as a novel prognostic biomarker and therapeutic target for patients with HCC.