Aggressive Breast Cancer Answers: What You Need to Know About HER2 Gene Amplification

It’s estimated about 1 in 8 women will develop breast cancer in the US alone. The term ‘breast cancer’ can sound very scary and overwhelming for both those diagnosed and their families, but most people don’t realize there are different types of breast cancer with varying degrees of aggression.

HER2-Positive breast cancer is a term many people will have never heard of, including those affected by this disease, when it actually makes up about 20% of all breast cancers. Whilst it’s considered to be more aggressive with a higher chance of spreading than some other cancers, treatment methods often tend to have better success as they can be more specific in targeting the HER2 gene responsible for this cancer.

So, if you or someone you know has recently received a HER2-Positive breast cancer diagnosis and you’re keen to learn more, here’s everything from HER2 basics to symptoms to treatment regarding this particular disease.

What is HER2?

In simple terms, HER2 (human epidermal growth factor receptor 2) is a gene that can contribute to the development of breast cancer.

The HER2 gene is responsible for making HER2 proteins which form breast cell receptors. These receptors control not only the growth of healthy breast cells but also their division and repair processes.

Because of the control and effect, HER2 has on the entire lifecycle of breast cells, if the HER2 gene doesn’t function correctly, it can make too many copies of itself (HER2 gene amplification). It’s these extra HER2 genes that cause otherwise healthy breast cells to grow and divide in a mutated, uncontrolled way. It’s this abnormal cell growth that causes cancer.


One of the most common symptoms of any type of breast cancer, including HER2-Positive is a lump in the breast. This is why it’s so important for women to regularly examine their breasts as, if a lump is present, you’ll likely discover it a lot quicker if you conduct regular self-examinations.

However, lumps aren’t the only symptoms of HER2-Positive breast cancer. Other signs may include:

  • Change in breast shape
  • Dimples on the breast surface or skin irritation
  • Breast swelling
  • Breast or nipple pain
  • Nipple discharge other than breast milk
  • Thickening or redness of the breast skin or nipple

If you notice any of these symptoms, visit a doctor immediately. Whilst some of these symptoms may not even be a sign of cancer, it’s always best to get checked out to be sure.

If it does turn out you have breast cancer after discovering one or more of these signs, it can be extremely scary and overwhelming. Take a look at SHARE Cancer Support to discover stories from real women diagnosed with breast cancer, as this may provide a greater insight and support for what you may be experiencing.


Upon finding out you have breast cancer, your doctor will then need to establish whether or not it’s HER2-Positive. There are multiple tests that can be used to do this, including:

  • The FISH (Fluorescence In Situ Hybridization) test – uses fluorescent pieces of DNA that will stick specifically to the HER2 gene. This test is used to discover if there are too many duplicates of the HER2 gene as, once the DNA has been applied, the cells containing HER2 can be counted under a microscope.
  • The IHC (ImmunoHistoChemistry) test – uses specific antibodies able to discover whether the HER2 gene is present in breast tissue. If it is, the antibodies will cause the cells to change color.

Whilst these tests are often very effective, just one may not provide clear enough results. If this is the case, your doctor will likely order a second test just to be sure.


As mentioned, there are multiple types of breast cancer. So, with regard to HER2-Positive, treatments that may be effective for other types may not work for this, which will make a huge difference in how your doctor decides to treat you.

Luckily, there are plenty of effective drugs that specifically target HER2 proteins that are used for treating this disease. In simple terms, they can kill the cells responsible for producing HER2, which will then block any more abnormal cancer cells from growing.

This greatly decreases the chance of HER2-Positive breast cancer returning, resulting in a high survival rate for sufferers of this disease.

Receiving any breast cancer diagnosis can be extremely scary and daunting, especially when presented with a term like HER2-Positive if you have no idea what it means. But now you know how it causes cancer and the processes it can involve, you’ll be much more prepared if you or someone you know were to receive such a diagnosis in the future.

Melissa Sakow is the Communications Director at SHARE Cancer Support, a non-profit organization founded in 1976 that is dedicated to building a network and community for women affected by breast and ovarian cancer.

Photo by maf04