Duplicitous Dispositions of Micro-RNAs (miRs) in Breast Cancer

Abstract

In 1993, a gene silencer known as lin-4 was first discovered in Caenorhabditis elegans and demonstrated to be critical for larval development. Lin-4 belongs to a family of signaling molecules known as non-protein coding microRNAs (miRNAs) which are not only highly conserved in humans, but also involved in the fundamental processes of oncogenesis. While miRNAs are not translated to proteins themselves, they are capable of regulating the expression and translation of other genes thus affecting a multitude of biological and pathological pathways as well as those essential to the malignant landscape. The aim of this chapter is to explore the diverse roles of miRNAs in the context of breast cancer. Following a brief overview of miRNA biogenesis, this chapter covers the production of miRNAs by tumor cells and stromal cells, onco-suppressor miRNAs, use as therapeutics, contribution to therapeutic resistance, and finally their emerging role as biomarkers. into the unique manifestation of BC in an individual. Given that they are actively released by tumor cells into the circulatory system, both monitoring and targeting miRNAs enables the diagnosis and monitoring of BC as well as the opportunity for the development of novel therapeutics. Future studies should employ well standardized methods for sample collection and multi-center global miRNA profiling to reveal novel nuances and robust results regarding miRNA signaling in the context of BC. Taken together, the emerging field of precision oncology may rely on understanding miRNA profiles.