HER2-positive early breast cancer 

Around 15 to 20 per cent of people with early breast cancer have a sub-type called HER2-positive breast cancer. These are breast cancers that have a higher-than-normal amount of the protein HER2 (human epidermal growth factor receptor 2) on the surface of the cancer cells. The HER2 proteins are receptors on breast cells that control how healthy breast cells grow, divide and repair themselves in an orderly way.  

Some breast cancer cells have a higher-than-normal amount of the HER2 protein (receptors) on their surface. This is called HER2 "overexpression" – it occurs when the HER2 gene doesn't work correctly and makes too many copies of itself. The HER2 receptors send many signals, causing the breast cancer cells to grow and divide at a faster rate than normal.   

Breast cancers with HER2 protein overexpression are called HER2-positive on a pathology report. All invasive breast cancers are tested for HER2 levels on a sample of breast tissue removed during a biopsy or surgery.  

The tissue is also tested to see whether it is hormone receptor positive. If the cancer has both HER2 and hormone receptors, it is sometimes called triple positive breast cancer. For more information about hormone receptor positive breast cancer and its treatment read hormone receptor positive breast cancer.  

Treatment   

HER2-positive breast cancer is often treated with a combination of:  

• Chemotherapy
• HER2-targeted therapies 
• Surgery   
• Radiotherapy
• Hormone-blocking therapy (if your cancer is also hormone receptor-positive).  

Many people with HER2-positive breast cancer will be offered neoadjuvant therapy and a HER2-targeted medication as their first treatment. This is followed by surgery and more HER2-targeted medication.   

Current research   

Clinical trials around the world are investigating treatments that combine HER2-targeted medication  with newer treatments such as immunotherapies and PI3K/AKT/mTOR inhibitors.  

The results of these trials may lead to new treatment combinations that improve outcomes for people with HER2-positive breast cancer.  

For more information speak to your doctor about any clinical trials that may be suitable for you.  

Getting support    

There are many different types of breast cancer and each one is treated differently. Talking to your treating team for information, advice and support is important.   

Some people find the support of others who have breast cancer helpful, as they share similar experiences. Our Online Network may help you connect with others in a similar situation.