Breast cancer cells that lack receptors for estrogen, progesterone and human epidermal growth factor receptor 2 (HER2) are known as triple negative breast cancer (ER-, PR-, HER2-).
Research suggests that younger women, women with the BCRA gene, and African American women are more likely to have triple negative breast cancer (TNBC). For African American women diagnosed with breast cancer, up to 40% have TNBC.
The disease is aggressive compared with other forms of breast cancer; it is more likely to recur and/or spread beyond the breast. It is more likely to be grade 3 (scales 1-to-3), which is a measure of how much the cells have mutated.
Even when caught early, TNBC has a lower five-year survival rate compared to other types (60% versus 80%). Of course, breast cancer grade as well as tumor size whether the cancer has spread beyond the breast will influence any individual prognosis.
According to Nancy Davidson, MD, 15-20% of breast cancers are triple negative. Davidson is executive director of the Fred Hutchinson Cancer Research Center and the Seattle Cancer Care Alliance, as well as head of medical oncology at the University of Washington School of Medicine.
As with almost every “type” of breast cancer, new research is identifying sub-types. Triple negative is no different; it has six.
According to Dr. Davidson, TNBC has four subtypes that can be identified by gene-expression
- basal-like 1 and 2 subtypes
- immunomodulatory subtype
- luminal androgen receptor subtype.
Because triple negative breast cancer has no ER, PR and HER2 receptors, it cannot be treated with hormone therapies or medications that work by blocking HER2.
The only proven method for systemic management of triple-negative breast cancer for both early-stage and metastatic settings is cytotoxic chemotherapy.
Learn more at the Triple Negative Breast Cancer Foundation.
Read the series