Functional Analysis of 3'UTR Variants Predisposing to Breast Cancer.

PURPOSE

Breast Cancer (BC) is the main female cancer diagnosed worldwide, and it has been described that few genes, such as , have a high penetrance for this type of cancer. In this manuscript, we were interested in evaluating the effect of 3'UTR variants on BRCA1 expression.

PATIENTS AND METHODS

To accomplish this objective, Whole Exome Sequencing (WES) data of 400 patients with unselected BC was used to filter variants located in the region of interest of gene, finding two of them (c.*36C>G and c.*369_373del). miRGate and miRanda in silico tools were used to predict microRNA (miRNA) interaction.

RESULTS

The two variants (c.*36C>G, c.*369_373del) were predicted to affect miRNA interaction. After cloning of 3'UTR into pMIR-Report vector, the construct was transfected into two BC cell lines (MDA-MB-231 and MCF-7), and the variant c.*36C>G evidenced overexpression of reporter gene luciferase, showing that the transcript was not being degraded by the miRNA in MDA-MB-231 cells.

CONCLUSION

The variant seems to protect against Triple Negative BC probably due to the expression level of miRNA in this particular cell line (MDA-MB-231). This is consistent with the clinical history of the patients who harbor BC Hormone Receptors positive (HR+).