Tumor metastasis, which accounts for the majority of deaths in breast cancer patients, is a process by which cancer cells acquire the ability to invade tissue and survive in other parts of the body. Dysregulation of the protein TGF-β is known to drive breast cancer metastasis, but the precise molecular mechanisms are unknown.
In this issue of the Journal of Clinical Investigation, researchers led by William Shiemann at Case Western Reserve University identified a microRNA, miR-181a, that is altered by TGF-β to promote metastasis.
Shiemann and colleagues found that miR-181a repressed the expression of a protein, BIM1, which causes cells to die when they detach from surrounding tissue, a key step in metastasis. Additionally, they determined that increased expression of miR-181a was correlated with decreased overall survival in breast cancer patients.
These findings suggest that miR-181a could potentially serve as a predictive marker for breast cancer metastasis.
Case Western Reserve University, Cleveland, OH, USA
TGF-β upregulates miR-181a expression to promote breast cancer metastasis
Journal of Clinical Investigation Dec. 17, 2012