The role of miRNA in selected tumors development: Potential use in diagnostics

MicroRNAs (miRNAs) are small ribonucleic acid molecules that, although not translated, perform an important regulatory function in eukaryotic cells. Their physiological function is to maintain cell homeostasis. Impaired miRNA expression can cause the development of many diseases including cancer. MiRNA biological activity is based on inhibiting the formation of proteins, including oncogenic and anti-oncogenic proteins. Mutations at the coding sites for such miRNAs can lead to overproduction or reduction of the production of the above-mentioned proteins. The discovery of miRNAs and understanding their role in the cell opened new ways for diagnosing cancer. Therefore, changes in the level of relevant miRNAs in the bloodstream or other bodily fluids can be a diagnostic marker of disease. Oncological diagnostics could be based on examining the patient's miRNA profile and comparing it with previously developed profiles of miRNAs changes associated with the occurrence of a given type of cancer. Information on changes in miRNA profiles that are key to regulating gene expression associated with tumorigenic processes could contribute to the development of experimental therapies based on restoring the original level of miRNA in cells and thereby restoring normal regulation of gene expression. New methods of silencing and enabling miRNA expression may, in the future, result in effective therapeutic solutions.