Patients with a newly identified subtype of triple-negative breast cancer (TNBC), referred to as BRCA-deficient subtype, demonstrate a markedly higher rate of anti-cancer responses to chemotherapy compared to other patients with TNBC.
Breast cancers that are not stimulated to grow from exposure to estrogen or progesterone and are HER2 (human epidermal growth factor receptor)-negative are called triple-negative breast cancers. Triple-negative breast cancers tend to be more aggressive than other breast cancers and have fewer treatment options.
Data has indicated that approximately one-third of patients with TNBC achieve a complete disappearance of their cancer when treated with chemotherapy. Researchers have been exploring possible molecular markers that might help determine subgroups of TNBC that achieve greater responses from chemotherapy than others so that patients who do not respond well to chemotherapy do not suffer unnecessary side effects, while those who do respond to chemotherapy can receive effective treatment.
Researchers recently examined genetic sequences (whole exome sequencing) from 29 patients with TNBC from the MD Anderson Cancer Center in Houston, Texas. Patients received initial therapy with the standard classes of chemotherapy agents, anthracyclines and taxanes. Of these patients, 18 had achieved a complete disappearance of their cancer, and 11 had extensive disease remaining, even after chemotherapy.
The genetic sequencing revealed that patients with the BRCA-deficient (BRCA-D) subtype had cancers that were much more sensitive to the cancer-killing effects of chemotherapy.
- 94.1% of patients with the BRCA-D subtype achieved a complete disappearance of their cancer, compared with only 16 6% of patients without the BRCA-D subtype.
- Patients with the BRCA-D subtype also achieved a significantly greater overall survival than those without the BRCA-D subtype.
The researchers concluded that these data reveal the BRCA-D subtype in TNBC appears to confer a significantly improved anti-cancer response rate and improved survival with standard chemotherapy. They suggested that additional studies to further understand and confirm this finding are warranted.
Reference: Jiang T, Shi W Wali V, et al. Predictors of chemosensitivity in triple negative breast cancer: an integrated genomic analysis. PloS. Available at: http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002193.