In Silico and Experimental Outcomes of the Expression of miR508-5p and miR-635 in Tumor Tissues of Patients with Breast Cancer

Background: Breast cancer (BC) is a malignant tumor that occurs in the epithelial tissue of the breast gland and has become the most common malignancy in women. Various studies have reported the effect of epigenetic changes, including DNA methylation and microRNAs, on breast carcinogenesis. microRNAs play an important role in the post-transcriptional regulation of genes and are important regulators of oncogenic pathways. Studying microRNAs in BC facilitates the development of targeted therapies and early detection of this cancer. Objectives: This study aimed to evaluate the expression level of miR-508-5p and miR-635 in BC tumor tissues compared to healthy marginal tissues. Methods: In silico analysis confirmed microarray datasets (GSE40525, GSE44124 and GSE45666) downloaded from the GEO database. The analysis was defined using the Affy packages in R software to screen remarkably dysregulated miRNAs attended by utilized to predict the potential biological processes and molecular pathways of miR-508-5p and miR-635. Experimental statistical significance of differences in miRNA relative expression results was analyzed by pair-wise fixed reallocation randomization test as a statistical model included in the REST (relative expression software tool). Results: GEO microarray data set, similar to qPCR results, showed that miR-508-5p was downregulated in the sample group by a mean factor of 0.327 (S.E.M range is 0.031-2.000). Moreover, miR-635 was upregulated in the sample group by a mean factor of 2.361 (S.E.M range is 0.250-16.000). Conclusion: miR-508-5p was downregulated, while miR-635 was upregulated in BC tissues. They may be proposed as diagnostic and therapeutic biomarkers for patients with BC.