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Breast Cancer: Hormones & Biomarker Status
When developing a personalized breast cancer treatment plan, our oncologists need to understand what is causing the breast cancer to grow. If the cancer cells have receptors for estrogen and/or progesterone, the treatment plan will include hormone therapy to block the growth signal. According to the American Cancer Society, two out of three breast cancer cases are hormone receptor-positive.
The breast cancer doctors at SCRI Oncology Partners in Nashville will also review biomarker test results when creating a personalized treatment plan. Biomarkers are genetic mutations, proteins, or other substances that can affect how breast cancer grows and responds to treatment. Besides estrogen and progesterone, the other most common biomarker is the overproduction of the HER-2 protein.
When the test results are available, the SCRI Oncology Partners team will review all available information, including hormone and biomarker status, stage, and lymph node involvement, to determine which treatments will work best and whether a clinical trial is available to the patient.
Breast Cancer Hormone Receptor Status
Your biopsy report, also called a pathology report, tells the oncologist whether the cancer cells are hormone receptor-positive (HR+) or hormone receptor-negative (HR-). If the tumor is HR-positive, it’s also important to know which specific hormone receptors are present.
Estrogen-receptor positive (ER+)
If the cancer cells are estrogen receptor-positive, they have receptors on the cancer’s cell surface for estrogen that allow the hormone to attach and send signals that encourage cancer growth.
Progesterone-receptor positive (PR+)
If the cancer cells are progesterone receptor-positive, they have receptors for progesterone that allow the hormone to bind to the cancer cell and fuel its growth.
Hormone Therapy
There are several available hormonal therapies for breast cancer that prevent hormones from binding to cancer cells, which slows cancer growth. The right hormone therapy will depend on which hormone receptors are present, whether the patient is considered high risks, and the patient’s menopause status. Your SCRI Oncology Partners oncologist will review all of the information and discuss the treatment with you. Many women take hormone therapy drugs for five to 10 years after breast cancer treatment is complete.
HER2 Breast Cancer Status
HER2 (human epidermal growth factor receptor 2) is a protein found on the surface of cells that helps regulate cell growth. When breast cancer cells produce too much HER2, they multiply quickly.
Testing is conducted to classify the tumor as:
- HER2-positive, which indicates an overexpression of the HER2 protein
- HER2-negative, meaning there is no excess HER2 protein
- HER2-low, where the cancer is not HER2-positive or HER2-negative, but still shows some HER2 expression
For HER2-positive women, targeted therapies are often used to block HER2 activity. Patients with HER2-low breast cancer may also benefit from certain HER2-directed treatments, depending on their specific situation.
Triple-Positive and Triple-Negative Breast Cancers
If breast cancer tests positive for estrogen receptors, progesterone receptors, and HER2, it is known as triple-positive breast cancer. There are several treatment options available for this type, and you will work with your breast cancer specialist to determine the best approach for you.
If the cancer tests negative for all three (estrogen receptors, progesterone receptors, and HER2), it is referred to as triple-negative breast cancer (TNBC). Triple-negative breast cancer tends to grow more quickly and does not respond to hormone therapy or HER2-targeted treatments, which means it will be treated differently compared to other types of breast cancer. Several clinical trials are underway to evaluate the best way to treat triple-negative breast cancer, including a new class of drugs called antibody drug conjugates (ADCs). Your SCRI Oncology Partners team will talk with you if there is a trial that you’re eligible to participate in.
Metastatic and Recurrent Breast Cancer Biomarker Testing
While testing for HER2 and hormone receptors is standard for nearly all patients, women with stage IV or recurrent breast cancer often undergo additional biomarker testing. This can include tests such as PDL1, broad genomic profiling, or other tests. These tests help oncologists at SCRI Oncology Partners identify appropriate targeted therapies or clinical trials that are most likely to be effective.
PD-L1 Testing
PD-L1 testing looks for a protein that allows cancer cells to hide from the immune system. Patients with metastatic, triple-negative breast cancer who are PD-L1–positive are likely to respond well to immunotherapy that blocks PD-L1 and helps the immune system recognize and attack cancer cells.
ESR1 Testing
An ESR1 mutation can cause some hormone therapies to be less effective, particularly aromatase inhibitors. Oncologists choose alternative hormone therapies that may be more effective for patients with this mutation.
Microsatellite Instability High (MSI-H)
MSI-H testing identifies tumors with a high number of genetic mutations, called microsatellites, which are essentially repeated DNA sequences. These cancers may respond well to immunotherapy, which helps the body’s immune system target and destroy cancer cells.
Additional Gene Testing Determines the Right Combination of Drug Therapies
For advanced or metastatic breast cancer, more extensive biomarker testing may include looking at other genes, such as:
- AKT1: Mutations in this gene can lead to uncontrolled cell growth
- PIK3CA: Plays a key role in normal cell function
- PTEN: Loss of function removes a natural brake on cell growth
- NTRK fusion: Creates abnormal proteins that drive cancer growth
The results from these tests help oncologists determine the most effective combinations of therapies tailored to your specific condition. If you are positive for one of these genetic changes, the oncologist will incorporate targeted therapies to counteract the genetic mutation’s effects.
Advancing Breast Cancer Care in Tennessee Using Biomarker Testing
The treatment planning process at SCRI Oncology Partners includes biomarker testing as an important step in delivering precise and personalized care to patients in the Nashville, Tennessee area, including Clarksville, Columbia, Dickson, Lebanon, White House, and Gallatin. For many of our patients, a clinical trial is available, giving them access to new or an improved way of using targeted therapies and hormone therapies to treat breast cancer.
If you were recently diagnosed with breast cancer and you’re located in the Nashville or Middle Tennessee area, schedule a consultation with our team. You will meet with the breast cancer surgeon and our medical oncologist to find out what is recommended for your specific needs. We also offer second opinions, allowing each patient to choose the path forward they feel most comfortable with.Â
We’re here to help, discover more resources
What is Metastatic Breast Cancer?
Metastatic breast cancer is breast cancer that has spread from the breast to other parts of the body. This is also referred to as advanced or stage 4 breast cancer.
Receiving an Abnormal Mammogram Report, What Next?
It is not unusual to get recalled after an initial screening mammogram. Additional imaging is often requested so that a clearer view of a particular area of breast tissue can be captured.
We’re here when you need us
If you were recently diagnosed or would like a second opinion, request an appointment with one of our experienced cancer doctors right here in Nashville.
We’re here when you need us
If you were recently diagnosed or would like a second opinion, request an appointment with one of our experienced cancer doctors right here in Nashville.
We’re here when you need us
If you were recently diagnosed or would like a second opinion, request an appointment with one of our experienced cancer doctors right here in Nashville.