Two Northwestern University scientists have identified a biomarker strongly associated with basal-like breast cancer, a highly aggressive carcinoma that is resistant to many types of chemotherapy. The biomarker, a protein called STAT3, provides a target for new therapeutics designed to treat this often deadly cancer.
Using breast cancer patient data taken from The Cancer Genome Atlas, molecular biologists Curt M. Horvath, PhD, and Robert W. Tell, PhD, used powerful computational and bioinformatics techniques to detect patterns of gene expression in two cancer subtypes. They found that a small number of genes are activated by STAT3 protein signaling in basal-like breast cancers but not in luminal breast cancers. Basal-like cancer is a category that includes a number of different breast cancers, including the highly aggressive triple negative cancer. According to Horvath, the findings, which were published online in the journal Proceedings of the National Academy of Sciences, suggest that a clinical study should be conducted of a STAT3-inhibiting drug in patients with basal-like and luminal cancers.
Previous research has found the STAT3 protein to be overactive in many breast cancers, but its role has not been well understood. Horvath and Tell's research is the first reported study to compare breast cancer subtypes and gene expression patterns associated with STAT3 in the human tumors. “This opens up the possibility that cancer subtype-specific signaling is driven by STAT3 and that STAT3 inhibitors may be more effective in patients diagnosed with basal-like cancers than in those with luminal cancers,” says Horvath.
The researchers’ intensive analysis used data from 825 breast cancer patients from across the country, each with hundreds of data points. The data included protein expression; protein phosphorylation, which indicates which signaling pathways are activated; and messenger RNA and microRNA expression. Read the study abstract.
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