Identification of Differentially Expressed miRNA by Next Generation Sequencing in Locally Advanced Breast Cancer Patients of South Indian Origin

PURPOSE: miRNAs are known to be aberrantly expressed in the serum, tissue, and Peripheral Blood Mononuclear Cells (PBMC) of cancer patients and could serve as potential noninvasive diagnostic markers for breast cancer. The aim of this study was to identify the differentially expressed miRNA using next-generation sequencing (NGS) from the paired PBMC samples from breast cancer patients and age-matched healthy individuals and explore their functional significance. METHODS: In this study, PBMCs were employed for the detection of miRNAs by NGS in locally advanced breast cancer (LABC) women of South Indian origin who were divided into three age groups, (a) 40yrs-50yrs (b) 50yrs-60yrs and (c) 60yrs-70yrs, compared with age-matched control groups. RESULTS: Four miRNAs (hsa-miR-192-5p, hsa-miR-24-2-2p, hsa-miR-3609, and hsa-miR-664b-3p) were found to be differentially expressed among LABC patients compared with age matched healthy women of the South Indian population. While miR-24-2-5p, miR3609, and miR-664b-3p were down-regulated, miR-192-5p was up-regulated. Gene Ontology (GO) annotations implicated miRNA with signaling pathways in peripheral nerve synapses, glutamatergic synapse, and cell morphogenesis, all of which play a pivotal role in the manifestation of cancer. CONCLUSION: Four miRNAs- 3 (While miR-24-2-5p, miR3609, and miR-664b-3p) downregulated and one upregulated (miR-192-5p) were identified as potential biomarkers for patients with locally advanced breast cancer. These markers could be validated in studies with a larger sample size.