BACKGROUND:

Mechanisms that lead to the reduced expression of BRCA1 in triple-negative breast cancer (TNBC) tumors are not fully understood. A possible cause is overexpression of miR-146a and miR-638, which regulate BRCA1 expression in other cancers.

OBJECTIVE:

To evaluate the expression of these microRNAs in relation to BRCA1 expression in TNBC tumors.

METHODS:

Expression of both microRNAs was assessed by real time qPCR using Taqman microRNA assays in TNBC tumors. Results were related to protein expression of BRCA1 and patient's survival.

RESULTS:

miR-146a and miR-638 were overexpressed in 36% and 59% of TNBC tumors, respectively. Overexpression was preeminent in BRCA1-deficient tumors and significantly associated to a better overall survival.

CONCLUSION:

Both miRNAs are potential biomarkers for improved overall survival in patients with BRCA1-deficient TNBC tumors.