Herceptin (Trastuzumab) for Breast Cancer Treatment
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Herceptin (Trastuzumab) and Breast Cancer: Patients and Caregivers
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Herceptin (Trastuzumab) Breast Cancer: Foundation

HER2 Testing Information | What is HER2?

HER2 Breast Cancer

Studies show that approximately 25% of breast cancer patients have tumors that are HER2+. HER2 stands for Human Epidermal growth factor Receptor 2. It is very important to find out your cancer's HER2 status. This is because HER2+ tumors tend to grow and spread more quickly than tumors that are not HER2+. In addition, the treatment of HER2+ breast cancer is different than the treatment of breast cancer that is not HER2+. Women who are uncertain of their cancer’s HER2 status should talk to their doctor.

HER2+ tumors represent 25% of breast cancer patients
HER2+ breast cancer is aggressive, so it is important to find out your cancer's HER2 status. This can help your doctor choose which treatments may be right for you.

 

How is HER2+ breast cancer different?

HER2 stands for Human Epidermal growth factor Receptor 2. Each normal breast cell contains copies of the HER2 gene, which helps normal cells grow. The HER2 gene is found in the DNA of a cell, and this gene contains the information for making the HER2 protein.

The HER2 protein, also called the HER2 receptor, is found on the surface of some normal cells in the body. In normal cells, HER2 proteins help send growth signals from outside the cell to the inside of the cell. These signals tell the cell to grow and divide.

In HER2+ breast cancer, the cancer cells have an abnormally high number of HER2 genes per cell. When this happens, too much HER2 protein appears on the surface of these cancer cells. This is called HER2 protein overexpression. Too much HER2 protein is thought to cause cancer cells to grow and divide more quickly. This is why HER2+ breast cancer is considered aggressive.

HER2+ breast cancer cell diagram

HER2+ breast cancer is aggressive, so it is important to find out your cancer's HER2 status. This can help your doctor choose which treatments may be right for you.

Inheriting the HER2 gene

Your tumor's HER2 status is not hereditary. This means that HER2 status is not passed down from your parents, and you can't pass it on to your children. However, there is a relationship between the genes in a person's DNA and breast cancer in general. Ask your doctor for more information about the relationship between genes and breast cancer.

Higher risk of breast cancer returning (recurrence)

Women with HER2+ breast cancer:

  • May be less likely to respond to certain treatments
  • May be more likely to have a recurrence (return) of their cancer


Women who are uncertain of their cancer's HER2 status should talk to their doctor.

HER2/neu-positive, HER2-overexpressing, and HER2+ breast cancer

HER2/neu is another name for HER2, which stands for Human Epidermal growth factor Receptor 2. HER2-overexpressing means there is too much HER2 protein/receptor on the surface of the cancer cells. HER2/neu-positive breast cancer and HER2-overexpressing breast cancer are exactly the same as HER2+ breast cancer.

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