From; Healthline.com
Human epidermal growth factor receptor 2 (HER2) is a protein that’s found on the surface of breast cells. Its normal function is to promote cellular growth and division.
Some breast cancers have higher-than-normal levels of HER2 protein receptors. These are called HER2-positive breast cancers. However, only a low percentage of breast cancers are HER2-positive.
Most breast cancers are HER2-negative. According to the National Cancer Institute (NCI), an estimated 78 percentTrusted Source of breast cancers are HER2-negative and don’t overexpress the HER2 receptor.
Continue reading below as we explore what it means to have HER2-negative breast cancer. We’ll cover the different HER2-negative subtypes, as well as diagnosis, treatment, and outlook.
HER2-negative breast cancer has a couple of different subtypes. Let’s take a look at these now.
HER2-negative, hormone receptor-positive
In addition to having a HER2 status, breast cancer cells also have a hormone receptor (HR) status. Estrogen and progesterone hormone receptors can be found on breast cancer cells. It’s worth noting that these receptors can also be found on healthy breast cellsTrusted Source.
A breast cancer is HR-positive when it has receptors for estrogen, progesterone, or both. Estrogen receptor-positive cancers are more common and are estimated to occur in about 75 percent of all breast cancers.
In HR-positive cancers, estrogen or progesterone can bind to the hormone receptors on breast cancer cells, helping to promote their growth and spread. As such, treatments for HR-positive breast cancers often targets hormone receptors.
HER2-negative, hormone receptor-negative
It’s also possible for a breast cancer to be negative for both HER2 and for hormone receptors. A breast cancer that’s HER2-negative, HR-negative is called triple-negative breast cancer.
This subtype of breast cancer is less common and often more aggressive.
Because triple-negative breast cancer lacks both HER2 and hormone receptors, it doesn’t respond to treatments that target these factors, but is often very responsive to immunotherapy. Additionally, it tends to recur more often than other subtypes of breast cancer.
Barbara Jacoby is an award winning blogger that has contributed her writings to multiple online publications that have touched readers worldwide.