Triple-negative breast cancer TNBC is a molecularly diverse 1 breast cancer subtype currently defined by what it lacks. Metastatic progression in this phenotype is typically marked by early relapse and a predominance of hepatic, pulmonary and central nervous system metastasis 5. Despite, or perhaps because of, its aggressive nature and the lack of current targeted treatments, significant clinical and laboratory research is providing nuanced treatment options.
March 28,by NCI Staff. Triple-negative breast cancer cells exhibit a great deal of heterogeneity, which makes it challenging to manage the disease. The combination therapy is the first FDA-approved regimen for breast cancer to include immunotherapy.
This means that the breast cancer cells have tested negative for hormone epidermal growth factor receptor 2 HER-2estrogen receptors ERand progesterone receptors PR. Since the tumor cells lack the necessary receptors, common treatments like hormone therapy and drugs that target estrogen, progesterone, and HER-2 are ineffective. Using chemotherapy to treat triple negative breast cancer is still an effective option.
To understand triple negative breast cancer, we first have to understand how breast cancer is classified. The tumor cells do not express either of the hormone receptors, or the HER2 receptor. About percent of breast cancers are triple negative, including many hereditary breast cancers that are driven by mutations in the BRCA1 or BCRA2 genes. TNBC is a devastating disease, and this is compounded by a lack of targeted therapies.
Triple-negative breast cancer is cancer that tests negative for estrogen receptors, progesterone receptors, and excess HER2 protein. These results mean the growth of the cancer is not fueled by the hormones estrogen and progesterone, or by the HER2 protein. So, triple-negative breast cancer does not respond to hormonal therapy medicines or medicines that target HER2 protein receptors.
Basal-like tumors have cells that look similar to those of the outer basal cells surrounding the mammary ducts. Most triple negative tumors are basal-like and most basal-like tumors are triple negative see figure below. About percent of breast cancers are triple negative or basal-like .
Disclosures: Clifford A. The content of this article has been reviewed by independent peer reviewers to ensure that it is balanced, objective, and free from commercial bias. No financial relationships relevant to the content of this article have been disclosed by the independent peer reviewers.
Triple-negative breast cancer constitutes a heterogeneous group of malignancies that are often aggressive and associated with a poor prognosis. Molecular characterization, while not a standard of care, can further subtype triple-negative breast cancer and provide insight into prognostication and behaviour. Optimal chemotherapy regimens have yet to be established; however, there have been advances in the systemic treatment of triple-negative breast cancer in the neoadjuvant, adjuvant, and metastatic settings.