HER2 (Human Epidermal growth factor Receptor 2) is a gene found in cells that is important for cell growth and survival. You may also sometimes see HER2 referred to by the name ERBB-2 (ERythroBlastic oncogene B-2).

In some people, the HER2 gene begins to mutate or change, which can be a driving cause of cancer. When changes in the HER2 gene cause lung cancer, it’s called HER2-positive or HER2+ lung cancer.

HER2-positive lung cancer can be found through biomarker testing. Biomarker testing tells your healthcare team what mutations or changes cancer cells have, and your results can help guide your healthcare team to the best treatment for you. People with stages 1B through 4B (IB through IVB) non-small cell lung cancer (NSCLC) should ask for comprehensive biomarker testing because it looks for all known biomarkers instead of just a few.

Scientists have found many different types of changes in HER2 in lung cancer. The most common change in HER2 found in people with lung cancer is an exon 20 insertion. Knowing your specific mutation is an important part of understanding your treatment plan.

• It occurs in about 2 out of every 100 cases (2%) of lung cancer.
• It most often occurs in a type of non-small cell lung cancer called adenocarcinoma.
• People diagnosed with HER2-positive lung cancer are more often women, people of Asian descent, and without a smoking history.

If your biomarker testing finds that you have a change in the HER2 gene, you will most likely be given a type of treatment known as targeted therapy. Targeted therapies are a special type of drug that can "target" cancer cells based on what makes them different from healthy cells. Because of this, healthy cells in the body are often not affected by targeted therapies, resulting in fewer side effects.

Most targeted therapy treatments are pills, but a few are given through an IV or a port (a small tube inserted in a vein). The drug names that end in -ib are pills and can be taken at home. The drug names that end in -mab are given through an IV at a cancer center.

Below is a list of targeted therapy drugs that are approved by the Food and Drug Administration (FDA) for use with NSCLC HER2 mutations. The FDA approves each drug for use in NSCLC at specific stages of the disease.

Everyone is different, and the side effects you may have while receiving treatment can vary. Some people experience side effects, while others don’t. Ask a member of your healthcare team about the possible side effects of your treatment and when to seek medical attention.