Irene Pylypenko
Published: 2020
Total Pages:
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"Breast cancer (BC) is the most common cancer in women worldwide, and current detection technologies have limitations. MicroRNAs (miRNAs) are small 18-22 nucleotide single-stranded RNAs and there is some evidence suggesting that miRNAs in blood samples may be used as diagnostic biomarkers for BC. The Norwegian Women and Cancer (NOWAC) is a large prospective study that has collected blood and tumor biopsy samples from BC patients and healthy tissue from age-matched controls. Using the Illumina microarray system, miRNA and messenger RNA (mRNA) expression profiles were generated for 96 breast cancer cases with matched controls. We identified thirty-eight miRNAs that discriminate between breast cancer and matched healthy controls, some of which (miR-210, miR-335, miR-145, miR-15a/b) have been previously identified as potential diagnostic markers in blood samples of breast cancer patients. Then, we applied three different miRNA target prediction tools to look for potential gene targets based on a simple negative association miRNA-target model. In our clustering analysis, the predicted gene sets identified in the matched mRNA expression profile did not follow the classical negative association miRNA-target model. Thus, inconsistent with the hypothesized model, as also supported by previous studies. Functional analysis of identified miRNAs and their predicted target genes identified some gene pathways involved in breast cancer, such as B cell receptor signaling pathway, BRCA1 expression network, and p53 a common oncogenic signal pathway. Although miRNAs show promising results as diagnostic markers in blood samples of breast cancer patients, there is much work to be done in understanding the relationship between miRNAs and their target genes in order to identify viable miRNA biomarkers for breast cancer"--