Cancer Associated MicroRNAs are Differentially Expressed in Triple Negative Breast Cancer and Normal Breast Cells

Breast cancer is a heterogeneous disease that is sub-categorized based on the expression of certain protein markers including estrogen and progesterone. Triple-negative breast cancer (TNBC) is a subtype of breast cancer that is characterized by its lack of the estrogen, progesterone and HER2/Neu protein receptors, and it has no known biomarkers for diagnosis and drug targeting. TNBC has a high mitotic index and primarily affects women of African origin. MicroRNAs are small non-coding RNA molecules that regulate oncogenic and tumor suppressive pathways in the cel1, and may potentially be used as biomarkers for the diagnosis and prognosis of TNBC. In this study, we compared the expression of microRNAs that play roles in cancer in TNBC cell lines (HCC1806, HCC70, and MDA-MB-157) and normal breast cells (AG11132). Microarray analysis revealed that microRNAs 21, 34a, 103, 141, and let-7a were shown to be differentially expressed in TNBC cells vs. the normal breast tissue cell lines. Quantitative-PCR confirmed the differential expression of the microRNAs in the TNBC cell lines vs the normal cells. These findings suggest that microRNAs could be used as potential biomarkers to diagnose TNBC and could potentially be used as drug-targeted therapies in the future.