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What is a triple-negative breast cancer?

Joane Goodroe
Nursing

This is a type of breast cancer which is estimated to be 10%-20% of all breast cancers. It is negative for estrogen receptor, progesterone receptor, and HER2. This makes it very difficult to find drug therapy that will attack the cancer.

Two of the largest studies to date looking at triple-negative breast cancer have found that reproductive factors — specifically, pregnancy and multiple childbirth — and obesity and lack of physical activity increase the risk for the disease.

In triple-negative breast cancer (TNBC), the cancer cells do not contain receptors for estrogen, progesterone or HER2. About 10% to 20% of all breast cancers are triple-negative. This type of breast cancer is usually invasive and usually begins in the breast ducts.

Healthy breast cells contain receptors for the hormones estrogen and progesterone. They also contain receptors for a protein called HER2, which stimulates normal cell growth. About 2 out of 3 women with breast cancer have cells that contain receptors for estrogen and progesterone, and about 20% to 30% of breast cancers have too many HER2 receptors. Breast cancer that is estrogen receptor (ER) and progesterone receptor (PR) positive can be treated with hormonal therapies. Breast cancer with excess amounts of HER2 can be treated with anti-HER2 drugs such as trastuzumab.

In women with TNBC, the malignant cells do not contain receptors for estrogen, progesterone or HER2. Breast cancer that is ER, PR and HER2 negative cannot be treated with hormonal therapies or medications that work by blocking HER2, such as trastuzumab.

Fortunately, triple-negative breast cancer can be treated with other drugs, such as chemotherapy and radiation.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.