Breast cancer treatment plans are often personalized and based on your specific stage and type of breast cancer. However, also critical that your oncologist knows which hormones, if any, are involved in the growth of the breast cancer. They will run some tests that indicate the hormone receptor status and HER2/neu status of the breast cancer tumor. The results then play a large role in the type of breast cancer treatment that’s recommended. There is typically one of the following four results:
- Estrogen-receptor positive or negative (ER+/-) - The breast cancer cells may or may not have receptors for the hormone, estrogen. ER+ results suggest that the cancer cells may receive signals from estrogen that could promote their growth.
- Progesterone-receptor positive or negative (PR+/-) - The breast cancer cells may or may not have receptors for the hormone, progesterone. PR+ results mean that the cancer cells may receive signals from progesterone that could promote their growth.
- HER2 positive or negative - HER2 (human epidermal growth factor receptor 2) is a protein that appears on the surface of some breast cancer cells and plays a role in how a healthy breast cell grows, divides, and repairs itself. Knowing whether they are present will affect the treatment that’s chosen.
- Triple-negative breast cancer - These breast cancer cells test negative for estrogen receptors, progesterone receptors, and HER2. Triple-negative breast cancer will be treated differently than the other types of breast cancer since hormones are not playing a role in the breast cancer’s growth.
Breast Cancer Hormone Receptor Status
It is possible for breast cancer cells to be fueled by estrogen or progesterone (the naturally occurring hormones in the female body) because of special proteins inside the tumor cells, called hormone receptors. When hormones attach to these hormone receptors, the cancer cells grow.
A hormone receptor status is either hormone receptor (HR) positive or hormone receptor (HR) negative.
- Hormone receptor-positive breast cancer cells have either estrogen (ER) or progesterone (PR) receptors. These breast cancers can be treated with hormone therapy drugs that lower estrogen levels or block estrogen receptors. HR-positive cancers tend to grow more slowly than those that are HR-negative. HR-positive cancers are generally more common in women after menopause.
- Hormone receptor-negative breast cancers do not have estrogen or progesterone receptors. These types of cancers will not benefit from hormone therapy drugs and typically grow faster than HR-positive cancers. HR-negative cancers are more common in women who have not yet gone through menopause.
HER2 Status in Breast Cancer
The behavior of breast cancer can be contributed to some genes and the proteins they make. These genes and their proteins can also affect how the disease responds to specific cancer treatments. HER2 (or human epidermal growth factor receptor 2) is a gene that can play a role in the development of breast cancer.
What does it mean to be HER2- negative or positive?
HER2-negative breast cancers do not have excess of the HER2 gene. These tumors will not respond to therapies that specifically target HER2 receptors.
HER2-positive breast cancers have too much HER2 protein or extra copies of the HER2 gene. These breast cancers tend to be fast-growing. HER2-positive breast cancer treatment typically includes targeted therapy drugs that slow the growth and kill these cancer cells.
It is typical for your doctor to test your HER2 status to determine if it is playing a role in your cancer so that your doctor can select a medication that addresses HER2 positive patients.