Evaluating serum levels of let-7e-5p, mir-151a-5p and mir-887-3p in breast cancer patients

Abstract

Initially, we discovered differentially expressed microRNAs (DEMs) in breast cancer tissue and serum by analyzing microarray data. The DEMs shared by tissue and serum were isolated. Then, we searched for novel miRNAs that had not been previously evaluated in breast cancer patient serum. In addition, the expression of these DEMs was also evaluated using RNA-seq data from the TCGA. Next, we collected 100 serum samples from breast cancer female patients and 100 samples of matched control serum. From these samples, total RNA was extracted and converted to cDNA. Real-time PCR (RT-PCR) was used to measure cDNA concentration. Finally, we compared the expression of selected DERMs between two groups using RT-PCR results. In addition, a ROC curve and Survival analysis were performed to estimate the diagnostic and prognostic value of particular DEMs. Finally, enrichment analysis was carried out to identify the role and significance of DEMs. Results: Let-7e-5p and mir-151a-5p were significantly up-regulated in the serum of breast cancer patients, while mir-887-3p was substantially down-regulated, according to our microarray data analysis. During the molecular phase, RT-PCR confirmed the microarray results indicating the overexpression of let-7e-5p and mir-151a-5p, as well as the intriguing downregulation of mir-887-3p. In addition, ROC curve analysis revealed that these miRNAs can distinguish cancer patients practically. In the case of prognostic, however, inconsistent results were observed, which may necessitate additional experiments. In the end, enrichment analysis confirmed the role of these miRNAs in multiple crucial cellular pathways, including regulation of the cell cycle, adhesion, gene transcription, protein translation, and cancer development in general.