Pathogenetic Role and Clinical Implications of Regulatory RNAs in Biliary Tract Cancer

SIMPLE SUMMARY: Non-coding ribonucleic acid (RNA) are small molecular structures with relevant functions in various disease processes. They might serve as biomarkers for the diagnosis and as targets for the treatment of biliary tract cancer. This is particularly relevant because current diagnostic methods of the condition only allow for late detection of the disease and therapeutic options are limited. This review aims to explore the possibilities of using non-coding RNA, in particular microRNA, to reduce mortality due to biliary tract cancer through earlier diagnosis of the condition and development of effective therapy. ABSTRACT: Biliary tract cancer (BTC) is characterised by poor prognosis and low overall survival in patients. This is generally due to minimal understanding of its pathogenesis, late diagnosis and limited therapeutics in preventing or treating BTC patients. Non-coding RNA (ncRNA) are small RNAs (mRNA) that are not translated to proteins. ncRNAs were considered to be of no importance in the genome, but recent studies have shown they play essential roles in biology and oncology such as transcriptional repression and degradation, thus regulating mRNA transcriptomes. This has led to investigations into the role of ncRNAs in the pathogenesis of BTC, and their clinical implications. In this review, the mechanisms of action of ncRNA are discussed and the role of microRNAs in BTC is summarised. The scope of this review will be limited to miRNA as they have been shown to play the most significant roles in BTC progression. There is huge potential in miRNA-based biomarkers and therapeutics in BTC, but more studies, research and technological advancements are required before it can be translated into clinical practice for patients.