What are Lung Cancer Genetic Tests?
Lung Cancer Genetic Tests are molecular tests that look for specific genetic changes (mutations, rearrangements, or other alterations) in lung cancer cells. These tests help healthcare providers understand the genetic characteristics of the tumor and determine whether targeted therapies may be effective.
The tests are most commonly performed in patients with non-small cell lung cancer (NSCLC), particularly lung adenocarcinoma, because several genetic alterations have approved targeted treatments. Unlike inherited genetic tests, these tests usually identify acquired (somatic) mutations that develop only in cancer cells and are not passed from parents to children.
How are the Tests Performed?
Preparation
- Preparing for Lung Cancer Genetic Tests depends on the type of sample collected.
- Fasting is usually not required.
- Inform your healthcare provider about your medical history and previous cancer treatments.
- Follow any instructions provided before biopsy or blood sample collection.
- Discuss the purpose and possible outcomes of testing with your healthcare provider.
Collection
- The sample collected depends on the testing method.
- Tumor tissue obtained during a lung biopsy or surgery is the preferred sample.
- If tissue is unavailable or additional testing is needed, a blood sample may be collected for liquid
- biopsy to detect circulating tumor DNA (ctDNA).
- The collection procedure varies depending on the sample type.
Lab Analysis
The collected sample is analyzed using advanced molecular techniques such as next-generation sequencing (NGS) or PCR to identify genetic alterations associated with lung cancer. The results help determine eligibility for targeted therapies and are interpreted alongside pathology findings, cancer stage, and other diagnostic information.
What are the Symptoms that Prompt these Tests?
Lung Cancer Genetic Tests are generally performed after a lung cancer diagnosis rather than to determine the cause of respiratory symptoms. They help identify genetic changes that may influence treatment decisions.
Situations and Conditions That May Prompt These Tests
Your healthcare provider may recommend Lung Cancer Genetic Tests if you have:
- A newly diagnosed non-small cell lung cancer (NSCLC)
- Lung adenocarcinoma
- Advanced or metastatic lung cancer
- Cancer that has returned after treatment
- A tumor that may respond to targeted therapy
- A need to identify the most appropriate personalized treatment
- Squamous cell lung cancer in selected cases
- Lung cancer with an unknown molecular profile
These tests may evaluate genetic alterations in EGFR, ALK, ROS1, BRAF, KRAS, MET, RET, NTRK, and HER2 (ERBB2), among other biomarkers.
What are Normal Ranges for These Tests?
Lung Cancer Genetic normal range do not have a single numerical value because they evaluate specific genetic changes in cancer cells.
Results may be reported as:
- Mutation Not Detected / Negative: No clinically significant genetic alteration was identified in the genes included in the test.
- Mutation Detected / Positive: A genetic alteration was identified that may help guide treatment.
- Indeterminate or Inconclusive: The test could not provide a definitive result, and additional testing may be necessary.
A negative result does not mean that the cancer is absent. It means that the specific genetic changes included in the test were not detected.
“The reference ranges vary depending on the laboratory and the methodology used. Individuals must consult their healthcare provider for correct interpretation of the results.”
What Happens if Test Results Show Abnormal Findings?
Abnormal Lung Cancer Genetic Test results indicate that a genetic alteration has been identified in the tumor.
Positive Genetic Findings
A detected mutation or alteration may help identify targeted treatment options. Examples include:
EGFR mutations: May allow treatment with EGFR-targeted therapies.
ALK rearrangements: May indicate eligibility for ALK-targeted therapies.
ROS1 rearrangements: May guide the use of ROS1-targeted treatment.
BRAF mutations: May make certain BRAF-targeted therapies appropriate.
KRAS mutations: Specific alterations, such as KRAS G12C, may have targeted treatment options.
MET alterations: Certain MET changes may be treated with targeted therapies.
RET rearrangements: May indicate eligibility for RET-targeted treatment.
NTRK fusions: May make TRK-targeted therapies an option.
HER2 (ERBB2) alterations: May provide information for treatment selection in appropriate cases.
Negative Results
A negative result means that no actionable genetic alteration was detected among the genes tested. However:
- The cancer may still have other genetic changes.
- The tumor may respond to treatments that do not depend on the tested mutations.
- Additional molecular testing may be recommended.
Inconclusive Results
An inconclusive result may occur if:
- The tissue sample contains too few cancer cells.
- The DNA or RNA quality is insufficient.
- The tumor sample is inadequate for testing.
- Your healthcare provider may recommend a repeat biopsy, liquid biopsy, or a broader genomic profiling panel.
Depending on the results, additional investigations may include BRAF Genetic Testing, EGFR Mutation Testing, ALK Gene Testing, KRAS Mutation Testing, or comprehensive Next-Generation Sequencing (NGS).
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