A brief review on long noncoding RNAs: a new paradigm in breast cancer pathogenesis, diagnosis and therapy.

With the development of technologies such as microarrays and RNA deep sequencing, long noncoding RNAs (lncRNAs) have become the focus of cancer investigations. LncRNAs, nonprotein-coding RNA molecules longer than 200 nucleotides, are dysregulated in many human diseases, especially in cancers. Recent studies have demonstrated that lncRNAs play a key regulatory role in gene expression and cancer biology through diverse mechanisms, including chromosome remodeling and transcriptional and post-transcriptional modifications. The expression levels of specific lncRNAs are attributed to prognosis, metastasis, and recurrence of cancer. LncRNAs are often involved in various biological processes, such as regulation of alternative splicing of mRNA, protein activity, and epigenetic modulation or silencing of the microRNAs, via discrete mechanisms. Deregulated levels of lncRNAs are shown in diverse tumors, including breast cancer. Based on latest research data, the tissue-specific expression signature of lncRNAs may represent the potential to discriminate normal and tumor tissue or even the different stages of breast cancer, which makes them clinically beneficial as possible biomarkers in the diagnosis and prognosis or therapeutic targets. In this brief review, we summarize some recent researches in the context of lncRNAs' roles in breast cancer pathogenesis and their potential to serve as diagnostic, predictive, and prognostic biomarkers and novel targets for breast cancer treatment.