The protein p66ShcA has shown promise as a biomarker to identify breast cancers with poor prognoses, according to a study published in the journal Molecular and Cellular Biology.
In this study, investigators led by Josie Ursini-Siegel from McGill University (Quebec, Canada) demonstrated p66ShcA to be highly enriched in breast cancers that have undergone epithelial to mesenchymal transition, a process that aids metastasis.
“We showed that elevated p66ShcA expression levels are strongly associated with expression of numerous epithelial to mesenchymal transition genes in all breast cancer subtypes,” explained 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 patient management and treatment decision-making. Breast cancers can currently be stratified into at leave five subtypes, each of which is associated with a different outcome. However, research has suggested that there is heterogeneity within these subtypes, reducing the reliability of subtype-based predictions.
Importantly, in this study p66ShcA levels were associated with acquisition of epithelial to mesenchymal transition in all subtypes, including luminal tumors. With 80% of all newly diagnosed breast cancers being luminal and HER2 subtypes, these findings are of particularly high clinical relevance.
“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, “concluded Ursini-Siegel.
Sources: Hudson J, Ha JR, Sabourin V et al. p66ShcA Promotes Breast Cancer Plasticity by Inducing an Epithelial to Mesenchymal Transition. Mol. Cell. Biol. doi:10.1128/MCB.00341-14 (2014) (Epub ahead of print); American Society for Microbiology press release