Maintenance of hormone responsiveness in luminal breast cancers by suppression of Notch.

ABSTRACT: Luminal breast cancers express estrogen (ER) and/or progesterone (PR) receptors and respond to hormone therapies. Basal-like "triple negative" cancers lack steroid receptors but are cytokeratin (CK) 5-positive and require chemotherapy. Here we show that more than half of primary ER(+)PR(+) breast cancers contain an ER(-)PR(-)CK5(+) "luminobasal" subpopulation exceeding 1% of cells. Starting from ER(+)PR(+) luminal cell lines, we generated lines with varying luminal to luminobasal cell ratios and studied their molecular and biological properties. In luminal disease, luminobasal cells expand in response to antiestrogen or estrogen withdrawal therapies. The phenotype and gene signature of the hormone-resistant cells matches that of clinical triple negative basal-like and claudin-low disease.

SUBMITTER: Haughian JM 

PROVIDER: S-EPMC3287001 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature