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EGFR Mutation Testing

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Also known as: Epidermal Growth Factor Receptor Mutation Analysis; HER-1; erbB-1
Formal name: Epidermal Growth Factor Receptor

Were you looking instead for Estimated Glomerular Filtration Rate, also known as eGFR? If so, see the article on eGFR.

The Test Sample

What is being tested?

EGFR is a short name for the epidermal growth factor receptor gene. This test detects mutations in the EGFR gene in cancer tissue. This information is useful in guiding treatment of non-small cell lung cancer.

The EGFR gene codes for a specialized protein called a receptor located on the surface of cells. Receptors recognize and bind to other substances, and the binding typically has a specific effect on the cells.

EGFR is one of a group of receptors called receptor tyrosine kinases that help regulate cell growth, division, survival, and death. This regulation is a very complex process involving the activation of a series of signals along various pathways. Receptor tyrosine kinases like EGFR transmit signals from the surface of the cell to within the cell.

In normal cells, the binding of epidermal growth factor to its receptor on the cell surface is an important signal that promotes cell proliferation. Certain mutations called "activating mutations" in the EGFR gene can result in excessive signaling for growth and uncontrolled proliferation of cancer cells.

Treatment that targets EGFR is a valuable molecular approach in cancer therapy. Examples of EGFR-targeted therapy include drugs such as gefitonib and erlotinib, which are small molecules called tyrosine kinase inhibitors (TKIs) that enter cancer cells and impede signaling.

These drugs have been shown to be useful in treating non-small cell lung cancer (NSCLC). Studies have shown that targeted therapy with these TKIs will only work in a subset of NSCLC with specific activating mutations in the EGFR gene. If an activating mutation is present, as detected with an EGFR mutation test, then the drugs directed against EGFR are much more likely to be effective and the patient should benefit from targeted therapy.

How is the sample collected for testing?

A sample of cancer tissue is obtained by performing a biopsy.

NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.

Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.

Is any test preparation needed to ensure the quality of the sample?

No test preparation is needed.