Receptor Testing

If you have been diagnosed with breast cancer, your biopsy sample will be tested for receptors. 'Receptors' are proteins found on the surface of cancer cells, that act like locks. Understanding your receptor status helps guide your treatment options. The three main receptors tested are: oestrogen receptor; progesterone receptor; and HER2. Oestrogen and progesterone are hormones that your body naturally produces - while HER2 is a growth factor protein. When these substances attach to receptors on cancer cells, they can signal the cells to grow and divide. Oestrogen receptor positive cancer is the most common type, affecting about seven in ten breast cancers. These cancers grow in response to the hormone oestrogen, and treatments that block or reduce oestrogen can be very effective. Progesterone receptor positive cancers respond to similar hormone blocking treatments. Many oestrogen receptor positive cancers are also progesterone receptor positive, which your team will consider when planning your individual care. HER2 positive cancers have too many HER2 receptors on their cell surfaces - which causes them to grow and divide more quickly than normal. About fifteen to twenty percent of breast cancers are HER2 positive. Targeted drugs like trastuzumab can block the HER2 protein and slow cancer growth very effectively. If your cancer has hormone receptors, you will likely be offered hormone therapy after your initial treatment. Drugs like tamoxifen, block oestrogen from reaching cancer cells - and these tablets are usually taken once daily for five to ten years. Aromatase inhibitors are another type of hormone therapy that work by stopping your body from making oestrogen. If your cancer is HER2 positive, you will usually be offered targeted therapy with trastuzumab - sometimes called Herceptin, and these treatments have greatly improved outcomes for patients. Some breast cancers are triple negative, meaning they do not have oestrogen, progesterone or HER2 receptors. These cancers require a different treatment approach, but effective options are available. Triple negative cancers do not respond to hormone therapy or HER2 targeted treatments, so they are usually treated with chemotherapy, and sometimes immunotherapy. Research into new treatments for triple negative cancer is also progressing rapidly. Your receptor status does not change how serious your cancer is; it simply tells your team which treatments will work best for you. Knowing your receptors allows treatment to be targeted to your particular cancer biology. This targeted approach gives you the best possible chance of successful treatment. If you are unsure about your receptor results, please ask your breast-care nurse or doctor to explain them to you clearly. Understanding why certain treatments are recommended helps you feel more confident about your care. Your receptor results are the key to unlocking treatments tailored specifically for your cancer. This personalized approach gives you the best chance of successful treatment, and our team will guide you through every decision ahead.