A review and analysis on the structure of miRNAs and their role as diagnostic and therapeutic biomarkers in various cancers

Cancer is a disease in which some of the body’s cells grow uncontrollably and spread to other parts of the body. Cancer can start almost anywhere in the human body, which is made up of trillions of cells. Normally, human cells grow and multiply (through a process called cell division) to form new cells as the body needs them. Sometimes this orderly process breaks down, and abnormal or damaged cells grow and multiply when they shouldn’t. These cells may form tumors, which are lumps of tissue. Considering the increasing number of cancer victims and the complexity of this disease in diagnosis, early awareness and treatment, it has led us to review one of the helpful and promising factors in cancer diagnosis and treatment in this review article. Micro ribonucleic acids (miRNAs) are non-coding ribonucleic acids that are evolutionarily conserved and have a length of ۱۸-۲۵ nucleotides. miRNAs control the expression of genes after transcription through mRNA degradation or inhibition of their translation. These molecular structures participate in the control of various physiological and pathological cellular processes (tumorigenesis and development, cell proliferation, metastasis, invasion and apoptosis), many of them can act as oncogenes or tumor suppressors. It has been almost two decades since the first link between microRNAs and cancer was established. In the ensuing years, this abundant class of short noncoding regulatory RNAs has been studied in virtually all cancer types. This tremendously large body of research has generated innovative technological advances for detection of microRNAs in tissue and bodily fluids, identified the diagnostic, prognostic, and/or predictive value of individual microRNAs or microRNA signatures as potential biomarkers for patient management, shed light on regulatory mechanisms of RNA–RNA interactions that modulate gene expression, uncovered cell-autonomous and cell-to-cell communication roles of specific microRNAs, and developed a battery of viral and nonviral delivery approaches for therapeutic intervention. Despite these intense and prolific research efforts in preclinical and clinical settings, there are a limited number of microRNA-based applications that have been incorporated into clinical practice. We review recent literature and ongoing clinical trials that highlight most promising approaches and standing challenges to translate these findings into viable microRNA-based clinical tools for cancer medicine.

Keywords:

miRNA , biomarker , diagnosis , prognosis , cancer , cardiovascular disease , sepsis , nervous system.