中文摘要：

Micro RNA（miRNA）是长约20-24nt的单链RNA，它通过与靶mRNA完全或不完全的互补配对，促进目标mRNA降解或抑制蛋白翻译．在细胞增殖、分化、凋亡、基因调控及疾病的发生中扮演重要的角色。miRNA是近几年生命科学研究的热点，已有研究表明miRNA与肿瘤的发生相关。阐明miRNA在癌症发生中的分子机制，对癌症的靶基因治疗策略具有重要意义。

英文摘要：

MicroRNAs （miRNAs） are an extensive class of short （20 -24 nt） non-coding single-strand RNAs widely expressed in plants and animals. These miRNAs appear to regulate gene expression post-transcriptionally by binding to the 3＇untranslated regions （3＇UTR） of specific target mRNAs and have a basic cellular function in proliferation, differentiation, apoptosis, and gene regulation. The specific modulation of several microRNAs has been recently associated to some human cancers. It suggests that these short molecules may represent a new class of genes involved in oncogenesis. Clarifying the molecular mechanisms of these miRNAs in the oncogenesis is important to consider miRNAs as potential therapeutic targets.