Role of microRNA in forming breast carcinoma

MicroRNA (miRNA) is a regulatory molecule which supervises various processes and gene expression. RNA polymerase II enzyme regulates miRNA gene transcription whereas miRNA biogenesis includes various proteins or enzymes. Starting from cell proliferation, cell cycle regulation and apoptosis are regulated by alteration in cancerous cells. Aberrant cell proliferation takes place and apoptosis is usually inhibited by oncogenic miRNA. The miRNA can be oncogenic or tumor suppressor in nature and their functions are opposite to each other. During tumorigenesis, the upregulation of oncogenic miRNA is mainly observed along with downregulation of tumor suppressors. The miRNA can degrade the target mRNA by using a slicer named argonaute protein (Ago) or by inhibiting the translation process. The miRNA may positively or negatively regulate the formation of tumor in breast by interfering with cellular activities. Thus, miRNA can be significantly used as a biomarker for monitoring breast cancer. In therapeutic intervention, the delivery of tumor suppressor miRNAs in a cancer patient can help in recovering from cancer. Different miRNAs regulate positively or negatively in these therapies. This review is mainly focused on the role of miRNA in breast carcinoma, its mechanisms and different therapies. It also includes miRNA biogenesis and different miRNAs involved in breast cancer.