An enzyme newly discovered to be overexpressed in some cases of triple-negative breast cancer (TNBC) represents a potential treatment target in this highly aggressive form of the disease.

“Efforts to improve the clinical outcome of [TNBC] have been hindered by the lack of effective targeted therapies,” acknowledged a research team led by Dr. Qiang Yu of the Agency for Science, Technology and Research Genome Institute of Singapore, in Proceedings of the National Academy of Sciences of the United States of America (PNAS) (2013;110[27]:11121-11126). “Thus, it is important to identify the specific gene targets/pathways driving the invasive phenotype to develop more effective therapeutics.”

Their own efforts in this area led Yu and colleagues to discover that a protein tyrosine phosphatase referred to as UBASH3B is overexpressed in about one-third of persons with TNBC. Overexpressed UBASH3B supports the malignant growth, invasion, and metastasis of TNBC, largely by modulating epidermal growth factor receptor (EGFR).

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The investigators also learned that early recurrence and metastasis of TNBC are more likely to occur in patients whose tumors have high levels of UBASH3B. However, deleting EGFR gene expression significantly inhibited TNBC cell invasive growth and lung metastasis in a mouse model.