EGFR MUTATION

EGFR Mutation

What it is

The EGFR (Epidermal Growth Factor Receptor) Mutation test is a molecular diagnostic test that detects genetic mutations in the EGFR gene. These mutations are most commonly associated with non-small cell lung cancer (NSCLC). Identifying EGFR mutations is critical because they can guide targeted therapy, as certain tyrosine kinase inhibitors (TKIs) are highly effective in patients with EGFR-mutated tumors.

Uses

This test is primarily used in oncology to determine whether a lung cancer patient is a candidate for EGFR-targeted therapies such as erlotinib, gefitinib, afatinib, or osimertinib. It is also used to monitor resistance mutations (e.g., T790M) that may arise during treatment, helping physicians choose the most effective therapy.

Symptoms That May Lead to the Test

The EGFR Mutation test is not based on general symptoms but is recommended in patients with diagnosed or suspected non-small cell lung cancer. It is especially useful when considering precision medicine approaches to treatment, and is often performed on tumor tissue or circulating tumor DNA (liquid biopsy).

Abnormal Results

Positive EGFR Mutation: Confirms the presence of specific mutations (such as exon 19 deletions, L858R, or T790M). This finding can guide targeted therapy decisions and predict treatment response.

Negative EGFR Mutation: Indicates no detectable EGFR mutations in the tumor. Alternative testing for other genetic drivers (e.g., ALK, ROS1, KRAS, PD-L1) may be recommended to guide treatment.

Risks

The test involves analyzing tumor tissue or blood samples. Risks are limited to those of the sample collection procedure—such as biopsy (pain, bleeding, infection) or blood draw (mild pain, bruising, dizziness). The genetic testing itself carries no physical risk.