Types of Breast Cancer: ER Positive, HER2 Positive, and Triple Negative
Triple-Negative Breast Cancer
Some breast cancers -- estimates range between 10% and 17% -- are known as “triple negative” because they lack estrogen and progesterone receptors and do not overexpress the HER2 protein. The majority of breast cancers associated with the breast cancer gene known as BRCA1 are triple negative.
These cancers generally respond well to adjuvant chemotherapy. Overall, however, they have a poorer prognosis than other types of breast cancer. So far, no targeted therapies like tamoxifen or Herceptin have been developed to help prevent recurrence in women with triple-negative breast cancer. Cancer experts are studying several promising targeted strategies aimed at triple-negative breast cancer.