Test Id : EGFRW

When this test is ordered, the EGFR Gene, Mutation Analysis, 51 Mutation Panel, Tumor will always be performed. All specimens without an EGFR mutation will be automatically reflexed to testing for the ALK (2p23) rearrangement. Specimens with an identified EGFR mutation will result in cancellation of the LCAF test.

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

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: 12 unstained, positively charged, unbaked slides or 2 hematoxylin and eosin-stained slides (will not be returned) and 10 unstained, positively charged, unbaked slides

Collection Instructions: Submit 12 unstained, positively charged, unbaked slides cut at 5-microns or 2 hematoxylin and eosin-stained slides and 10 unstained, positively charged, unbaked slides with 5-micron thick sections of the tumor tissue.

If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

Molecular Genetics: Inherited Cancer Syndromes Patient Information (T519)

Oncology Test Request (T729)

See Specimen Required

Identifying non-small cell lung cancers that may benefit from treatment with epidermal growth factor receptor -targeted therapies or anaplastic lymphoma kinase inhibitors

When this test is ordered, the EGFR Gene, Mutation Analysis, 51 Mutation Panel, Tumor will always be performed. All specimens without an EGFR mutation will be automatically reflexed to testing for the ALK (2p23) rearrangement. Specimens with an identified EGFR mutation will result in cancellation of the LCAF test.

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

Targeted cancer therapies are defined as antibody or small molecule drugs that block the growth and spread of cancer by interfering with specific cell molecules involved in tumor growth and progression. Multiple targeted therapies have been approved by the FDA for treatment of specific cancers. Molecular genetic profiling is often needed to identify targets amenable to targeted therapies and to minimize treatment costs and therapy-associated risks. Epidermal growth factor receptor (EGFR) protein 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 non-small cell lung cancer (NSCLC). As a result, the mutation status of EGFR can be a useful marker by which patients are selected for EGFR-targeted therapy.

Rearrangements of the anaplastic lymphoma kinase (ALK) locus are found in a subset of lung carcinomas (generally EGFR wildtype tumors) and their identification by fluorescence in situ hybridization (FISH) may guide important therapeutic decisions for the management of these tumors. The fusion of the echinoderm microtubule-associated protein-like 4 (EML4) gene with the ALK gene results from an inversion of chromosome band 2p23. The ALK-EML4 rearrangement has been identified in 3% to 5% of NSCLC with the majority occurring in adenocarcinoma and younger male patients who were light or nonsmokers. Recent studies have demonstrated that lung cancers harboring ALK rearrangements are resistant to EGFR tyrosine kinase inhibitors but may be highly sensitive to ALK inhibitors, like crizotinib (Xalkori). The drug crizotinib works by blocking certain kinases, including those produced by the abnormal ALK gene. Clinical studies have demonstrated that crizotinib treatment of patients with tumors exhibiting ALK rearrangements can halt tumor progression or result in tumor regression. The ALK/EML4 FISH assay is an FDA-approved companion diagnostic test for crizotinib, which was recently approved by the FDA to treat certain patients with late-stage (locally advanced or metastatic), non-small cell lung cancers that harbor ALK gene rearrangements. It is useful for the identification of patients with lung cancer who will benefit from crizotinib therapy.

An interpretive report will be provided.

An interpretive report will be provided.

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

A negative (wildtype) EGFR result does not rule out the presence of other activating mutations in the EGFR

gene.

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

The ALK fluorescence in situ hybridization (FISH) test is intended to be used for therapeutic purposes in pulmonary carcinoma. This FISH assay does not rule out other chromosome abnormalities.

While results of these tests may indicate the likely response to EGFR-targeted therapies or  anaplastic lymphoma kinase (ALK)-inhibitor therapies, selection of treatment remains a clinical decision.

1. Sharma SV, Bell DW, Settleman J, Haber DA: Epidermal growth factor receptor mutations in lung cancer. Nat Rev Cancer. 2007 Mar;7(3):169-181. doi: 10.1038/nrc2088

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. 2012 Sep 1;131(5):E822-829. doi: 10.1002/ijc.27396

3. Mok TS: Personalized medicine in lung cancer: what we need to know. Nat Rev Clin Oncol. 2011 Aug 23;8(11):661-668. doi: 10.1038/nrclinonc.2011.126

4. Cheng L, Alexander RE, Maclennan GT, et al: Molecular pathology of lung cancer: key to personalized medicine. Mod Path 2012 Mar;25(3):346-369. doi: 10.1038/modpathol.2011.215

All ordered specimens will undergo EGFR testing. The EGFR test is a qualitative polymerase chain reaction (PCR)-based assay employing fluorescently labeled probes that are used to detect exon 18 (G719A/C/S), exon 21 (L858R,

L861Q), exon 20 (T790M, S768I) mutations, exon 19 deletions and exon 20 insertions of the EGFR gene.

A pathology review and macrodissection to enrich for tumor cells is performed prior to slide scraping.

The ALK fluorescence in situ hybridization (FISH) test uses an FDA-approved ALK dual-color, break-apart rearrangement probe kitset. The ALK probe consists of 2 probes that flank the ALK gene region at 2p23 (Abbott Molecular). Five-micron sections of formalin-fixed, paraffin-embedded tissue specimens are cut and mounted on positively-charged glass slides. The selection of tissue and the identification of target areas on the hematoxylin and eosin-stained slide are performed by a pathologist. The probe set is hybridized to the appropriate target areas and 2 technologists analyze 25 interphase nuclei each (50 total). Results are reported based on the guidelines include with the probe kit and package insert with the results expressed as the percent abnormal nuclei.(Unpublished Mayo method)

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This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

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

88381-Microdissection, manual

88271 x 2-DNA Probe (if appropriate)

88274-Interphase in situ hybridization (if appropriate)

88291-Interpretation and report (if appropriate)