EGFR Mutation Analysis
- Sample Type
- Tissue Biopsy / Plasma
- Fasting
- No
- Unit
- N/A
Function
The Epidermal Growth Factor Receptor (EGFR) is a protein on the surface of cells that helps them grow and divide. Mutations in the EGFR gene can cause the receptor to be permanently 'turned on,' leading to the uncontrolled cell proliferation characteristic of certain cancers, particularly Non-Small Cell Lung Cancer (NSCLC).
Why it is Ordered
This test is vital for patients diagnosed with advanced NSCLC. It is a 'companion diagnostic' used to determine if the cancer is likely to respond to Tyrosine Kinase Inhibitors (TKIs) like Erlotinib, Gefitinib, or Osimertinib. Testing for specific mutations (like Exon 19 deletions or L858R) allows for personalized targeted therapy.
Associated Conditions
- Non-Small Cell Lung Cancer (NSCLC): The primary condition where EGFR testing is standard of care.
- Acquired Resistance: The T790M mutation is a specific variant that often develops after initial treatment, causing resistance to first-generation TKIs.
- Adenocarcinoma: EGFR mutations are most commonly found in lung adenocarcinomas, particularly in non-smokers and women.
Check Your Result
Check Your Result
Enter your lab result to see where you stand compared to the standard reference range.
Why Context Matters
The primary confounding factor is 'tumor heterogeneity'—the mutation might be present in one part of a tumor but not another, leading to a false negative if the biopsy sample is small. 'Liquid biopsies' (plasma) have lower sensitivity than tissue biopsies. Furthermore, the quality of the tissue fixative (formalin) used by the lab can degrade DNA, leading to failed or inaccurate sequencing results.
Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.
Clinical References
Source-of-truth databases and clinical guidelines for EGFR Mutation Analysis:
Official Sources
- EGFR Mutation Testing - Testing.comTesting.com
- EGFR gene: MedlinePlus GeneticsMedlinePlus
Research & Guidelines
- PubMed: EGFR Mutation Analysis Clinical GuidelinesNCBI / PubMed
Related Indicators
Medically Reviewed by Dr. Binoy Babu, MBBS
Board Certified Doctor • 10+ Years Clinical Experience
Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.
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