microRNAs：小分子在肿瘤中的重要作用

microRNAs是一类新型保守的微小非编码单链RNA，成熟的microRNAs通过与靶基因mRNA碱基形成不完全配对，引起mRNA降解及转录抑制。研究表明，microRNAs对细胞增殖、细胞分化和细胞凋亡具有重要的调控作用，microRNAs的表达异常与肿瘤的发生发展密切相关，肿瘤中既存在肿瘤抑制作用的microRNAs，也存在肿瘤促进作用的microRNAs。因此，microRNAs分子虽小，却在肿瘤发生、发展的过程中作用重大。

microRNAs: a small molecule but an important role in tumor

microRNAs are a new/class of small, evolutionarily conserved, non-protein-coding RNA molecules. Mature microRNAs exert their gene regulatory activity primarily by imperfectly base pairing to their target mRNAs, leading to mRNA degradation or translational inhibition. Recent studies have verified that microRNAs play a key role in diverse biological processes, including cell proliferation and differentiation as well as apoptosis. Further studies showed that microRNAs as oncogenes and tumor suppressors are involved in the tumor formation and development. Accordingly, microRNAs as a kind of small RNA molecules play an important role in tumorigenesis.