Triple-negative breast cancer is defined by what receptor status?

Triple-negative breast cancer is specifically characterized by the absence of three key receptors: estrogen receptors (ER), progesterone receptors (PR), and the human epidermal growth factor receptor 2 (HER2). This means that the cancer does not express any of these receptors, which differentiates it from other breast cancer subtypes that may be driven by the presence of one or more of these hormonal or growth factor receptors.

The lack of these receptors in triple-negative breast cancer is significant because it often indicates that the cancer may not respond to hormonal therapy (such as tamoxifen or aromatase inhibitors, which target estrogen) or therapies that target HER2 (such as trastuzumab or pertuzumab). This receptor status has implications for treatment options and prognosis, making it vital to accurately identify and classify this type of breast cancer.

In contrast, the other receptor statuses indicated by the other choices do not define triple-negative breast cancer, and therefore, those options do not accurately describe its classification.