Survival of patients with hepatocellular carcinoma (HCC) remains poor, which is largely attributed to active angiogenesis. However, the mechanisms underlying angiogenesis in HCC remain to be discovered. In this study, we found that long noncoding RNA associated with microvascular invasion in HCC (lncRNA MVIH) (lncRNA associated with microvascular invasion in HCC) was generally overexpressed in HCC. In a cohort of 215 HCC patients, the overexpression of MVIH was associated with frequent microvascular invasion (P = 0.016) and a higher tumor node metastasis stage (P = 0.009) as well as decreased recurrence‐free survival (RFS) (P < 0.001) and overall survival (P = 0.007). Moreover, the up‐regulation of MVIH served as an independent risk factor to predict poor RFS. We also found that MVIH could promote tumor growth and intrahepatic metastasis by activating angiogenesis in mouse models. Subsequent investigations indicated that MVIH could activate tumor‐inducing angiogenesis by inhibiting the secretion of phosphoglycerate kinase 1 (PGK1). Additionally, in 65 HCC samples, MVIH expression was inversely correlated with the serum level of PGK1 and positively correlated with the microvessel density. Conclusion: Deregulation of lncRNA MVIH is a predictor for poor RFS of HCC patients after hepatectomy and could be utilized as a potential target for new adjuvant therapies against active angiogenesis. (HEPATOLOGY 2012;56:2142–2153)

Hepatitis B virus (HBV) can integrate into the human genome, contributing to genomic instability and hepatocarcinogenesis. Here by conducting high-throughput viral integration detection and RNA sequencing, we identify 4,225 HBV integration events in tumour and adjacent non-tumour samples from 426 patients with HCC. We show that HBV is prone to integrate into rare fragile sites and functional genomic regions including CpG islands. We observe a distinct pattern in the preferential sites of HBV integration between tumour and non-tumour tissues. HBV insertional sites are significantly enriched in the proximity of telomeres in tumours. Recurrent HBV target genes are identified with few that overlap. The overall HBV integration frequency is much higher in tumour genomes of males than in females, with a significant enrichment of integration into chromosome 17. Furthermore, a cirrhosis-dependent HBV integration pattern is observed, affecting distinct targeted genes. Our data suggest that HBV integration has a high potential to drive oncogenic transformation.

Recently, microRNAs in cancer development have attracted much attention, but their roles in tumorigenesis are still largely unknown. In this study, a functional role of miR-22 in hepatocellular carcinoma (HCC) development has been identified. Quantitative real-time PCR was used to determine the level of miR-22 transcript in HCC clinical samples, and its correlation with disease-free survival was determined using Kaplan–Meier method. Restoration of miR-22 expression was carried out in HCC cell lines to assess its influence on HCC cell proliferation and tumourigenicity. In the 160 paired HCC tissue samples, miR-22 expression was downregulated in HCC, and low miR-22 expression in HCC was predictive of poor survival in HCC patients. Functional studies indicated that ectopic expression of miR-22 significantly inhibits HCC cell proliferation and tumourigenicity. Furthermore, histone deacetylase 4 (HDAC4), known to have critical roles in cancer development, was proved to be directly targeted and regulated by miR-22. Furthermore, HDAC4 was upregulated in miR-22-downregulated HCC tissues, suggesting that downregulation of miR-22 might participate in HCC carcinogenesis and progression through potentiation of HDAC4 expression. In addition, cell proliferation was also suppressed by knockdown of HDAC4 or treatment with HDAC inhibitor trichostatin A in HCC cell lines. miR-22, downregulated in HCC, has an anti-proliferative effect on HCC cells both in vitro and in vivo. Furthermore, miR-22 may have considerable potential in identification of the prognosis and application of cancer therapy for HCC patients.