HER2 and Lung Cancer

Support for this educational program provided by Amgen, AstraZeneca, Blueprint Medicines, Bristol Myers Squibb, Genentech, Lilly Oncology, Merck, Novartis and Pfizer.

When tumor tissue is looked at under a microscope, physicians can see what type of cancer it is. But physicians can also look for changes in the DNA of the tumor that might be causing the tumor to grow. Sometimes these changes are called biomarkers or molecular markers.

One way to think about it is that our DNA is like an instruction manual. If there is a typo in the instruction manual, the cell receives wrong instructions and can grow into cancer. Biomarker testing looks for those typos, so physicians know if you are a candidate to receive a targeted therapy that directly addresses those typos. 

An error in the HER2 gene (pronounced her-2) is one biomarker that physicians look for in non-small cell lung cancer. If you have non-small cell lung cancer, it is important to talk to your doctor about comprehensive biomarker testing to see if you have an error in the HER2 gene or another biomarker. An error in a gene that causes cancer is sometimes also called an oncogene. The results of this testing influence your treatment options. To learn more about biomarker testing, visit Lung.org/biomarker-testing. 

What is the HER2 oncogene?

HER2 (also known as ERBB2) is a signaling receptor in the cell. That means it helps the cell receive certain messages from other cells. It belongs to a family of signaling receptors that also includes EGFR, so sometimes you may hear the two talked about together.  If you think of a mutation as a typo in the DNA, you can have missing or added words in the DNA, sometimes called deletions or insertions. You can also have parts of the DNA where there are too many copies which is called an amplification. You can also have places where the DNA is misspelled, which is called a point mutation. There are HER2 point mutations, amplifications and insertions. The most meaningful type of HER2 mutation for treating lung cancer is called an exon 20 insertion.   

Who is most likely to have a HER2 oncogene?

HER2 mutations tend to be more common in adenocarcinoma non-small cell lung cancer patients with little to no smoking history. About 2% of lung cancer patients have HER2 mutations.  

How do you know if you have a HER2 oncogene?

In general, there are two ways to detect HER2 oncogenes. The best way is through comprehensive next-generation sequencing (NGS). This type of testing places tissue from a patient’s tumor (gathered from a biopsy) in a machine that looks for a large number of possible biomarkers at one time. There may be some situations where a patient can’t undergo the biopsy needed to perform NGS, and so liquid biopsy is recommended. A liquid biopsy can look for certain biomarkers in a patient’s blood. Talk to your doctor to make sure one of these tests was performed.  

Learn more about the different types of biomarker tests here.

What is the course of treatment like for someone with a HER2 oncogene?

Several HER2 targeted therapies are currently under investigation. These are pills that block or inhibit HER2 from causing uncontrolled cell growth. Physicians and patients should discuss participation in clinical trials of these therapies. But right now, standard of care for first-line treatment for lung cancer patient with stage four lung cancer with HER2 mutations is chemotherapy with or without immunotherapy. 

Work with your doctor to discuss your goals and options each time you have to make a treatment decision. The three big questions to ask are:

1. What is the goal of this treatment?
2. What are the potential side effects?
3. What other options do I have?

Research is happening at a rapid pace and your doctor should be up to date on the recommendations for your specific type of lung cancer. If you don’t feel comfortable with the answers you are receiving, do not hesitate to seek out a second opinion.