Circulating microRNAs as Novel Minimally Invasive Biomarkers for Breast Cancer

Using a novel approach to extract miRNAs from the circulation followed by real-time quantitative polymerase chain reaction analysis, levels of a panel of 7 candidate miRNAs were quantified in tissue and blood specimens of 148 patients with breast cancer and 44 age-matched and disease free control individuals.

We report that cancer-specific miRNAs were detected and significantly altered in the circulation of breast cancer patients, and that increased systemic miR-195 levels in breast cancer patients were reflected in breast tumors. Furthermore, we identified that circulating levels of miR-195 and let-7a decreased in cancer patients postoperatively, to levels comparable with control subjects, following curative tumor resection. Finally, we found that specific circulating miRNAs correlated with certain clinicopathological variables, namely nodal status and estrogen receptor status.