miRNA expression and its clinical implications for the prevention and diagnosis of non-small-cell lung cancer

miRNAs are a recently discovered category of small noncoding RNAs that regulate gene expression at the post-transcriptional level. Altered expressions of miRNAs are reported in a variety of human cancers and may associate with cancer pathogenesis, apoptosis and cell growth, thereby functioning as either oncogenes or tumor suppressors. Accumulating evidence indicates that deregulation of miRNA contributes to tumor initiation and progression and hence, has clinical value in several human cancers, including non-small-cell lung cancer. This article discusses the current knowledge of miRNAs in risk assessment, prevention, early diagnosis, prognosis and their possible role as oncogenes or tumor suppressors in the pathogenesis of non-small-cell lung cancer.