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

HER2 testing is performed with the tumor sample removed during surgery or using a needle.

There are two types of tests available to determine HER2 status: Fluorescence In Situ Hybridization (FISH) and ImmunoHistoChemistry (IHC).

A FISH test checks to see whether or not the cancer cells have a normal number of HER2 genes. Using a special microscope the pathologist looks at cancer cells to see how many HER2 genes there are compared with some other normal genes
An IHC test measures how much HER2 protein there is on the surface of the cancer cells. The test is scored on a scale of 0 to 3+
Accurate testing is important; your pathology report may contain inconclusive results. Sometimes one test may not be enough to determine with certainty whether your tumor is HER2+. Ask your doctor to discuss the results of your pathology report, explain how your tumor's HER2 status was determined, and to let you know whether another test may be necessary.

..Who is Herceptin for?
Herceptin is approved for the adjuvant treatment of HER2-overexpressing, node-positive or node-negative (ER/PR-negative or with one high-risk feature) breast cancer. Herceptin can be used several different ways:

As part of a treatment regimen including doxorubicin, cyclophosphamide, and either paclitaxel or docetaxel
With docetaxel and carboplatin
As a single agent following multi-modality anthracycline-based therapy
Herceptin in combination with paclitaxel is approved for the first-line treatment of HER2-overexpressing metastatic breast cancer. Herceptin as a single agent is approved for treatment of HER2-overexpressing breast cancer in patients who have received one or more chemotherapy regimens for metastatic disease.

What important safety information should I know about Herceptin?
Herceptin treatment can result in heart problems, including those without symptoms (reduced heart function) and those with symptoms (congestive heart failure). The risk and seriousness of these heart problems were highest in people who received both Herceptin and a certain type of chemotherapy (anthracycline). Your doctor will stop or strongly consider stopping Herceptin if you have a significant drop in your heart function.

You should be monitored for decreased heart function before your first dose of Herceptin, and frequently during the time you are receiving Herceptin and after your last dose of Herceptin. If you must permanently or temporarily stop Herceptin due to heart problems, you should be monitored more frequently. In one study with Herceptin and certain types of chemotherapy, an inadequate blood supply to the heart occurred.

Some patients have had serious infusion reactions and lung problems; fatal infusion reactions have been reported. In most cases, these reactions occurred during or within 24 hours of receiving Herceptin. Your Herceptin infusion should be temporarily stopped if you have shortness of breath or very low blood pressure. Your doctor will monitor you until these symptoms go away. If you have a severe allergic reaction, swelling, lung problems, inflammation of the lung, or severe shortness of breath, your doctor may need to completely stop your Herceptin treatment.

Worsening of low white blood cell counts associated with chemotherapy has also occurred.

Herceptin can cause low amniotic fluid levels and harm to the fetus when taken by a pregnant woman.

The most common side effects associated with Herceptin were fever, nausea, vomiting, infusion reactions, diarrhea, infections, increased cough, headache, fatigue, shortness of breath, rash, low white and red blood cells, and muscle pain.

Because everyone is different, it is not possible to predict what side effects any one person will have. If you have questions or concerns about side effects, talk to your doctor.

Please see the Herceptin full prescribing information including Boxed WARNINGS and additional important safety information.

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