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Epidermal Growth Factor Receptor (EGFR) Gene Mutation Analysis, Non−Small-cell Lung Cancer (Single-base Extension)

CPT To be determined. Updates will be made when available.
Synonyms
  • Erlotinib Responsiveness in NSCLC, EGFR Mutation Analysis
  • Gefitinib Responsiveness in NSCLC, EGFR Mutation Analysis
  • IRESSA® Responsiveness in NSCLC, EGFR Mutation Analysis
  • Non−Small-cell Lung Cancer, EGFR Mutation
  • Tarceva® Responsiveness in NSCLC, EGFR Mutation Analysis

Test Details

Turnaround Time

5 - 7 days

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Use

In non-small cell lung cancer, many mutations in EGFR are associated with responsiveness to EGFR tyrosine kinase inhibitor (TKI) therapy. In contrast, some mutations in EGFR are associated with resistance to EGFR TKI therapy, including T790M and EGFR exon 20 insertions. The T790M mutation is a known mechanism of resistance and is commonly associated with relapse following initial therapy with EGFR TKI.

Special Instructions

Please provide a copy of the pathology report. Please direct any questions regarding this test to customer service at 800-345-4363. A subsequent blood sample may be requested in order to confirm the somatic origin of an identified mutation.

Limitations

The EGFR test is designed to detect mutations in exon 18, 19, 20 and 21 of the EGFR gene. These mutations account for >99% of all reported EGFR mutations in NSCLC patients. Samples with results reported as "no mutation detected" may harbor EGFR mutations that are not detected by the assay.

Detection of mutation is dependent on sample integrity and the amount of amplifiable DNA present in the specimen. The methods used in this assay are highly selective and, depending on the total amount of DNA present, can detect approximately 2% to 20% of mutant in a background of wild-type genomic DNA.

This test was developed and its performance characteristics determined by Labcorp. It has not been cleared or approved by the Food and Drug Administration.

Methodology

SNaPshot Multiplex PCR (primer extension-based method)

References

Lindeman NI, Cagle PT, Aisner DL, et al. Updated Molecular Testing Guideline for the Selection of Lung Cancer Patients for Treatment With Targeted Tyrosine Kinase Inhibitors: Guideline From the College of American Pathologists, the International Association for the Study of Lung Cancer, and the Association for Molecular Pathology. Arch Pathol Lab Med. 2018 Mar;142(3):321-346. PubMed 29355391
 
NCCN Clinical Practice Guidelines in Oncology. Non-Small Cell Lung Cancer. Version 3.2020.

Specimen Requirements

Information on collection, storage, and volume

Specimen

Formalin-fixed, paraffin-embedded (FFPE) tissue block or slides from NSCLC

Volume

Five unstained slides and one matching H&E-stained slide at 10 μM or formalin-fixed, paraffin-embedded tissue block

Minimum Volume

Two unstained slides and one matching H&E-stained slide at 10 μM (samples with >4 mm² and ≥50% tumor content are preferred)

Container

Slides or blocks

Causes for Rejection

Tumor block containing insufficient tumor; tissue or tumor fixed in a heavy metal fixative; broken or stained slides

Collection

Submit blocks/slides at room temperature.

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