中文摘要：

微小RNA（microRNA，miRNA）是一类长度为二十几个核苷酸的内源性非编码调控RNA，通过序列特异性翻译抑制或mRNA裂解来调控基因表达，参与细胞发育、增殖、分化、凋亡等一系列重要生物学进程。近期的研究发现，miRNA具有癌基因和抑癌基因的作用，在肿瘤的发生和发展中起着重要的作用。已发现若干miRNA直接参与肝细胞癌的发生和发展，miRNA表达谱与肝细胞癌的诊断、分期、进展和预后等相关。作为一类新的分子靶标，miRNA应用于肝细胞癌的诊断和生物治疗具有广阔的前景。

英文摘要：

MicroRNAs （miRNAs） are endogenous non-coding RNAs, about 20 nucleotides in length. They play a pivotal role in the regulation of genes involved in diverse biology processes such as cell development, proliferation, differentiation and apoptosis by the translation repression or mRNA degradation. Recent evidence has suggested that miRNA alterations are involved in the initiation and progression of various human cancer including hepatocellular carcinoma （HCC）, and miRNA-expression profiling of HCC has ide.ntified signatures associated with diagnosis, staging, progression and prognosis. As a novel molecular target, miRNAs holds great promise in diagnosis and biotherapy of HCC.