New biomarker highly promising for predicting breast cancer outcomes

Aug. 29, 2014

A protein named p66ShcA shows promise as a biomarker to identify breast cancers with poor prognoses, according to research published ahead of print in the journal Molecular and Cellular Biology.

In breast cancer, a process called “epithelial-to-mesenchymal transition” aids metastasis. Epithelial cells line surfaces which come into contact with the environment, such as skin and the gastrointestinal tract. Mesenchymal cells are a type of cell in embryonic tissue and in connective tissue, where they form very loose contacts with one-another. Tumor cells lose mature epithelial characteristics, such as the ability to adhere to their neighbors, and gain those of the mesenchymal cells, which enable them to move easily through the cellular matrix and into the bloodstream. That enables their metastatic migration to distant organs and tissues.

In this study, researchers led by Josie Ursini-Siegel, PhD, of McGill University, show that the protein p66ShcA is highly enriched in breast cancers that have undergone epithelial-to-mesenchymal transition. “We showed that elevated p66ShcA expression levels are strongly associated with expression of numerous epithelial-to-mesenchymal transition genes in all breast cancer subtypes,” says Ursini-Siegel. “Thus, p66ShcA may serve as one of the first prognostic biomarkers to identify poor outcome breast cancers regardless of their molecular subtype.”

The ability to predict prognosis is critical to management of treatment. A patient with a good prognosis can be spared aggressive treatment, with its often-unpleasant side effects. But failure to apply aggressive treatment to an aggressive tumor can lead to death.

“By understanding the underlying mechanisms that contribute to tumor heterogeneity and metastatic progression, including the epithelial-to-mesenchymal transition, we hope to be better able to guide the development of prognostic and therapeutic strategies to improve patient care,” says Ursini-Siegel. Read the study abstract.

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