Triple-negative breast cancer is an aggressive form of breast cancer wherein tumors lack expression of three proteins.
The three are estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 (HER2).
Triple-negative breast cancer is able to grow and spread more quickly than other forms of breast cancer.
Also, because its cancer cells lack hormone receptors, specialists cannot treat them with hormone therapy. The only treatment for these types of cancer is chemotherapy.