microRNA Expression in Prospectively Collected Blood as a Potential Biomarker of Breast Cancer Risk in the BCFR

Abstract

Background/aim: Current breast cancer risk assessment models have moderate discriminatory ability. We evaluated whether microRNA (miRNA) expression profiles in peripheral blood mononuclear cells (PBMC) could be a useful biomarker of risk in high-risk women.

Materials and methods: Next-generation sequencing evaluated miR expression in PBMCs of 20 women who were unaffected at the time of recruitment and later diagnosed with breast cancer and 20 unaffected women.

Results: Out of the 5 miRNAs identified as potential risk markers, miR-144-3p, miR-451a, miR-144-5p and miR-183-5p were up-regulated, while miR-708-5p was down-regulated. We then evaluated these miRs in 28 additional case/control pairs using quantitative reverse transcription polymerase chain reaction (PCR). None of the results in the validation sample were statistically significant possibly due to the much longer interval between blood collection and diagnosis in the validation set.

Conclusions: Differentially expressed miRNAs from PBMCs may be potential non-invasive biomarkers for breast cancer prediction. Larger prospective studies are required to confirm whether our findings with specific miRNA loci were related to timing before diagnosis.

Keywords: biomarker; microRNA; mononuclear cells.