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Test Code EGFRT EGFR Gene, Mutation Analysis, 29 Mutation Panel, Tumor

Useful For

Identifying non-small cell lung cancers that may respond to epidermal growth factor receptor-tyrosine kinase inhibitor therapies

Disease States

  • Non-small cell lung cancer

Additional Tests

Test ID Reporting Name Available Separately Always Performed
SLIRV Slide Review in MG No, (Bill Only) Yes

Testing Algorithm

When this test is ordered, slide review will always be performed at an additional charge.

Method Name

Polymerase Chain Reaction (PCR) Analysis

Reporting Name

EGFR Gene, Mutation Analysis, Tumor

Specimen Type

Varies


Specimen Required


Pathology report must accompany specimen in order for testing to be performed.

 

Preferred:

Specimen Type: Tissue

Container/Tube: Tissue block

Collection Instructions: Submit a formalin-fixed, paraffin-embedded tissue block.

 

Acceptable:

Specimen Type: Tissue

Container/Tube: Slides

Specimen Volume: 1 stained and 5 unstained

Collection Instructions: Submit 1 slide stained with hematoxylin and eosin and 5 unstained, non-baked slides with 5-micron thick sections of the tumor tissue.


Specimen Minimum Volume

Formalin-fixed, paraffin-embedded (FFPE) tissue block (preferred) or 1 slide stained with hematoxylin and eosin and 5 unstained, nonbaked slides with 5-microns thick sections of the tumor tissue.

Specimen Stability Information

Specimen Type Temperature Time
Varies Ambient (preferred)
  Frozen 
  Refrigerated 

Reject Due To

Note: No specimen should be rejected. If specimen not received at appropriate temperature or in wrong anticoagulant, include note to laboratory. If questions, contact laboratory.

Clinical Information

Lung cancer is the leading cause of cancer-related deaths in the world. Non-small cell lung cancer (NSCLC) represents 70% to 85% of all lung cancer diagnoses. Small molecular agents that target the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) protein are approved for the treatment of locally advanced or metastatic NSCLC as a second- or third-line regimen. Subsequently, randomized trials have suggested that targeted agents alone or combined with chemotherapy may be beneficial in maintenance and first-line settings. Because the combination of targeted therapy and standard chemotherapy leads to an increase in toxicity and cost, strategies that help to identify the individuals most likely to benefit from targeted therapies are desirable.

 

EGFR is a growth factor receptor that is activated by the binding of specific ligands, resulting in activation of the RAS/MAPK pathway. Activation of this pathway induces a signaling cascade ultimately leading to cell proliferation. Dysregulation of the RAS/MAPK pathway is a key factor in tumor progression for many solid tumors. Targeted therapies directed to tumors harboring activating mutations within the EGFR tyrosine kinase domain (exons 18-21) have demonstrated some success in treating a subset of patients with NSCLC by preventing adenosine 5'-triphosphate (ATP)-binding at the active site. Gefitinib and erlotinib have been approved by the FDA for use in treating patients with NSCLC who previously failed to respond to the traditional platinum-based doublet chemotherapy. These 2 drugs have also recently been shown to increase progression-free and overall survival in patients who receive EGFR-tyrosine kinase inhibitor therapy as a first-line therapy for the treatment of NSCLC.

 

Agents such as gefitinib and erlotinib, which prevent ATP binding to EGFR kinase, do not appear to have any meaningful inhibitor activity on tumors that demonstrate the presence of the specific drug-resistant EGFR mutation T790M. Therefore, current data suggest that the efficacy of EGFR-targeted therapies in NSCLC is confined to patients with tumors demonstrating the presence of EGFR- activating mutations such as L858R, L861Q, G719A/S/C, S768I or small deletions within exon 19 and the absence of the drug-resistant mutation T790M. As a result, the mutation status of EGFR can be a useful marker by which patients are selected for EGFR-targeted therapy.

Reference Values

An interpretive report will be provided.

Interpretation

An interpretive report will be provided.

Cautions

A negative (wild type) result does not rule out the presence of a mutation that may be present but below the limits of detection for this assay (approximately 10%).  

 

A negative (wild type) result does not rule out the presence of other activating mutations in the epidermal growth factor receptor (EGFR) gene.

 

The predictive value of epidermal growth factor receptor (EGFR) testing applies to EGFR--tyrosine kinase inhibitors (TKI) therapies, not to other therapeutic agents.

 

Not all patients that have activating EGFR mutations detected by this assay respond to EGFR-TKI therapies.

 

Rare polymorphisms exist that could lead to false-negative or false-positive results.

Clinical Reference

1. Sharma SV, Bell DW, Settleman J, Haber DA: Epidermal growth factor receptor mutations in lung cancer. Nat Rev Cancer 2007;7(3):169-181

2. Gao G, Ren S, Li A, et al: Epidermal growth factor receptor-tyrosine kinase inhibitor therapy is effective as first-line treatment of advanced non-small-cell lung cancer with mutated EGFR: a meta-analysis from six phase III randomized controlled trials. Int J Cancer 2011;131(5):E822-829

3. Mok TS: Personalized medicine in lung cancer: what we need to know. Nat Rev Clin Oncol 2011;8:661-668

Method Description

A PCR-based assay employing Scorpions real-time PCR and allele-specific PCR technologies is used to test for 29 mutations within exons 18 through 21 of the EGFR gene:

G719A

2239_2256del8

G719S

2239_2248TTAAGAGAAG->C

G719C

2239_2258->CA

2235_2249del15

2240_2251del12

2235_2252->AAT

2240_2257del8

2236_2253del18

2240_2254del15

2237_2251del15

2239_2251->C

2237_2254del18

2307_2308ins9

2237_2255->T

2310_2311insGGT

2236_2250del15,

2319_2320insCAC

2238_2255del18,

S768I

2238_2248->GC

T790M

2238_2252->GCA

L858R

2239_2247del9

L861Q

2239_2253del15

 

 

A pathology review and macro dissection to enrich for tumor cells is performed prior to DNA extraction.(Package insert: EGFR RGQ PCR Kit, Qiagen, Valencia, CA, 2011)

Day(s) and Time(s) Performed

Monday through Friday; 10 a.m.

Analytic Time

5 days

Specimen Retention Time

Unused portions of blocks will be returned. Unused slides are stored indefinitely.

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

EGFR Gene, Mutation Analysis, 29 Mutation Panel, Tumor 

81235-EGFR (epidermal growth factor receptor) (eg, non-small cell lung cancer) gene analysis, common variants (eg, exon 19 LREA deletion, L858R, T790M, G719A, G719S, L861Q)

 

Slide Review

88381-Microdissection, manual

LOINC Code Information

Test ID Test Order Name Order LOINC Value
EGFRT EGFR Gene, Mutation Analysis, Tumor In Process

 

Result ID Test Result Name Result LOINC Value
53246 Result Summary 50397-9
53247 Result 21665-5
53248 Interpretation 69047-9
53249 Specimen 31208-2
53250 Source 31208-2
54442 Tissue ID No LOINC Needed
53251 Released By 18771-6