Biomarkers
After you have been diagnosed with breast cancer, your doctor will also inform you if your cancer has a biomarker, and if it does, which biomarker(s) it has. A biomarker is a protein that may be expressed by your cancer cells that your doctor will use to determine the most effective treatment line for your cancer. There are three main types of biomarkers associated with breast cancer: ER, PR, HER2.
ER (Estrogen Receptor)
ER positive breast cancer cells have estrogen receptors that allow the cancer cells to use the naturally produced hormone estrogen to grow and multiply. ER + cancers are often treated with hormone (endocrine) therapy to block estrogen and inhibit the growth of cancer cells.
PR (Progesterone Receptor)
Similar to ER positive, PR positive cancer cells feed off of the hormone progesterone; the cancer cells have progesterone receptors that allow them to use the hormone to grow and multiply. PR positive patients will also most likely receive hormone therapy to block the growth of cancer cells.
HER2
Cancer cells that overexpress the HER2 gene produce an excessive amount of the HER2 protein that promotes growth. HER2 can be targeted with specific treatment lines (HER2 targeted therapy) to block HER2 signaling and inhibit cancer cell growth.
There are four main groups that cancers are classified in based on which biomarkers the cancer cells have. For more specific information regarding treatment options, click on your type of cancer in the menu, or select treatment options.
HR (ER and PR) Positive and HER2 Negative
(LUMINAL A)
In this case, your cancer expresses ER and PR but does not express HER2. This means that your cancer is hormone driven. Treatment options vary, but include surgery (for stages 0-III), hormone therapy (most common systemic therapy for this type of cancer), radiation therapy, chemotherapy and/or targeted therapy.
ER positive, PR negative, and HER2 positive
(LUMINAL B)
In this case, your cancer expresses ER and HER2, but does not express PR. Treatment options vary, but include surgery (for stages 0-III), hormone therapy, radiation therapy, chemotherapy and/or targeted therapy.
HR (ER and PR) Negative and HER2 Positive
(HER2 POSITIVE)
In this case, your cancer expresses HER2 but does not express ER and PR. Therefore, your cancer is not hormone driven. Treatment options vary, but include surgery (for stages 0-III), radiation therapy, chemotherapy, and/or targeted therapy.
Triple Negative (ER, PR, and HR negative)
(BASAL-LIKE/TNBC)
In this case, your cancer does not express any of the three common biomarkers. Triple negative breast cancers are harder to treat than the other subtypes, but there are still treatment options. Treatment options vary, but include surgery (for stages 0-III), radiation therapy, immunotherapy, targeted therapy, and chemotherapy. Chemotherapy is the most common type of treatment for TNBC, and is given to most people who have it.