What is an Exon 20 insertion mutation?
To know what exon 20 is, it is important to know what an exon is. When looking at a cancer cell’s DNA, the DNA is considered the cookbook, genes (EGFR) are the recipes, and an exon is a specific recipe with an error that leads to uncontrolled cell growth known as cancer cell formation.
Who is likely to have an Exon 20 insertion mutation?
Patients that are positive for an EGFR mutation may also be positive for an Exon 20 mutation. Exon 20 accounts for up to approximately 1 in 30 lung cancers and is more commonly found in people who never smoked and in Asian persons.
How do you know if you have an Exon 20 insertion mutation?
Exon 20 can sometimes be harder to detect with traditional biomarker testing techniques known as PCR. Newer advanced biomarker tests known as Next Generation Sequencing (NGS) can often have a higher chance of detecting the mutation. NGS may be covered through Medicare & Medicaid insurance if the patient is enrolled in a clinical trial and specific criteria are met.
What are the treatment options for Exon 20 insertion mutation patients?
If you are diagnosed with the Exon 20 mutation, your care team may recommend chemotherapy, and immunotherapy. These treatment options work across a broad range of cancers.
Exon 20 mutations are resistant to typical EGFR Tyrosine Kinase Inhibitors (TKIs).
There are currently two targeted therapies approved by the U.S. Food and Drug Administration (FDA) to treat the Exon 20 mutation:
There are also new advancements in science on the horizon and can be found in clinical trials.
What Should You Do Next?
If you are positive for NSCLC but have not received biomarker testing, ask your doctor about comprehensive biomarker testing.
If you are an EGFR positive patient, ask your doctor if you have an Exon 20 mutation, if NGS is right for you, and if your insurance will cover the test.
It is also important to ask your doctor about all your treatment options and their side effects and potential clinical trials that may be right for you.
Page last updated: April 11, 2023