PO-525 Molecular signatures of circulating microRNAs as early breast cancer biomarkers

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IntroductionBreast cancer is the leading cause of cancer death among women. The number of human diagnosed with breast cancer has been increased specially in middle and low countries. Early detection is a key to reduce cancer deaths. Biological fluids such as blood hold good opportunities to identify new non-invasive biomarkers. One the new and the promising classes of circulating cancer biomarkers is the microRNAs (miRNAs). These molecules are tissue-specific, are remarkably stable in several biological samples and have others intrinsic characteristics that make attractive as biomarkers. Thus to identify molecular signatures of circulating miRNAs that can be correlated with molecular subtypes of breast cancer in early stages can be an useful in clinical practice. We applied a new screening technology to determine the expression profile of circulating RNAs and to correlate molecular subtypes of early stage breast cancer and compare with healthy women.Material and methodsFifty-four patients with early-stage breast cancer paired with twenty-seven women without breast cancer risk (controls). Total RNA was obtained from serum of cases and controls and the expression profile of differentially expressed serum miRNAs was obtained using the nCounter panel from NanoString Technology. Statistical analyses were performed in program R. The interaction networks miRNAs-genes predicted were constructed in the Cytoscape program and the functional enrichment analysis was applied to identify the molecular pathways related with onset and cancer progression.Results and discussionsWe identify miRNAs significantly differentially expressed specific for each molecular subtype: 19 miRNAs for the luminal A subtype, 8 miRNAs for the luminal B subtype, 10 miRNAs for the luminal B HER 2 positive subtype and 4 miRNAs for the subtype in HER2-enriched. In addition, in silicoanalyses showed genes targets of miRNAs in important molecular pathways associated with carcinogenicity by molecular subtypes.ConclusionOur results showed that there is a group of circulating miRNAs as potential of early biomarkers in breast cancer patients associated with molecular subtypes of breast cancer when compared with healthy women.