Evaluation of expression levels of mir-181a-3p and mir-450a-5p in serum of women with breast cancer

Abstract

With the advancement of technology in recent years, the limitations of cancer studies to one or a few genetic factors or epigenetic factors have been overcome. In this regard, microarray and sequencing technologies have provided the possibility of studying all genetic factors (mRNAs) and epigenetic factors including miRNAs and lncRNAs in a comprehensive manner. Among these, investigating the changes in miRNAs as one of the epigenetic factors that play a role in gene expression regulation post-transcriptionally is of great importance. Methods and Materials: To identify differentially expressed miRNAs, two microarray datasets related to serum of women with breast cancer were analyzed, and two miRNAs with significant expression changes in the serum of breast cancer patients compared to healthy individuals were selected. Subsequently, by extracting RNA and synthesizing cDNA from 100 serum samples of cancer patients and 100 serum samples of healthy individuals, the expression levels of mir-450a-5p and mir-181a-3p were measured using Real-time PCR technique. Statistical analyses of expression differences and biomarker analysis were performed on the obtained data. Finally, by conducting enrichment analyses, the role of these miRNAs in regulating cellular processes was determined and utilized. Results: Initially, the roles and cellular and molecular mechanisms regulated by selected miRNAs, which are involved in the occurrence and progression of various diseases including various types of cancers, were investigated through enrichment analyses. Enrichment analysis is an analytical method used in molecular biology and genetics to examine genomic data. In this method, a set of genes that play a role in a specific biological pathway or process is examined. Then, the relationship of this set of genes with various biological features is investigated using genomic data. Molecular experiments on clinical cases showed a significant increase in the expression of mir-181a-3p in breast cancer patients, while no significant expression changes were observed in relation to mir-450a-5p. In this regard, mir-181a-3p can be useful in significantly distinguishing healthy individuals from affected individuals, although it is not considered as a biomarker with high sensitivity and specificity. Furthermore, survival analysis performed using the kmplotter web-based software determined the prognostic value of the mentioned miRNAs.