Lab Test

EGFR Mutation Analysis

EGFR, Lung cancer mutation analysis, non-small cell lung cancer

Test Codes

SOFTPATH: MEMUG, SOFT GENE: MEMUT, SOFT LAB: MEMUG

Specimen Collection Criteria

Collect: Paraffin-embedded tissue. A paraffin block must be submitted. (Slides or paraffin shavings are not acceptable.) Submit 10 % formalin-fixed, paraffin-embedded block with corresponding H&E slide. Tissue should be well fixed and well processed. Average tissue size 5.0 mm2. Specimens requiring decalcification (e.g. bone biopsies) should be treated with Mol decal agent (EDTA) only. 

  • DNA will be assessed for quality. If it is deemed unacceptable, testing will be cancelled with client notification.
  • The specimen must be accompanied by a completed requisition and must contain the patient name, date of birth, collection date, ordering physician, and source of specimen.

Physician Office/Draw Specimen Preparation

Maintain paraffin-embedded tissue at room temperature (20-25°C or 68-77°F) until transport.

Preparation for Courier Transport

Transport: Paraffin-embedded tissue, at room temperature (20-25°C or 68-77°F).

Rejection Criteria

  • Tissue treated with decalcifying agents other than Mol decal (EDTA)Fixatives other than 10% neutral buffered formalin (e.g. alcohol, zinc formalin). 
  • Improper labeling or inadequate information.

  • Less than 10 percent tumor cellularity, at discretion of medical director.

  • Poor quality and/or quantity of extracted genomic DNA.

Testing will be cancelled on specimens meeting the above criteria with client notification.

Inpatient Specimen Preparation

Specimens at Royal Oak may be sent to the Surgical Pathology tube station, #201. In-house specimens are also picked up by a Surgical Pathology assistant every hour on the hour.

In-Lab Processing

Unstained sections of 5-µm thickness are cut from selected tissue blocks. The number of sections cut and the need for macro-dissection are determined by the pathologist, based upon the amount of available tissue and the tumor cellularity.

Maintain specimens at room temperature (20-25°C or 68-77°F) until testing.

Storage

Specimen Stability for Testing

Room Temperature (20-25°C or 68-77°F); indefinitely
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable
 
Specimen Storage (post testing)

Room Temperature (20-25°C or 68-77°F): 7 days

Specimen Storage (DNA post testing):

Frozen (-25 to -15°C): 2 months

Laboratory

Royal Oak Clinical Molecular Pathology Laboratory

Performed

Once per week, usually Thursday.
Results available within 10 business days.

Reference Range

No EGFR mutation detected.

Test Methodology

Polymerase Chain Reaction (PCR) amplification of target sequences with real time fluorescent detection.

This assay detects the most prevalent somatic mutations in exons 18, 19, 20, and 21. Namely, Exon 18: E709A(c.2126 A>C), E709D(c.2127A>C and c.2127A>T), E709G(c.2126G>C), E709K(c.2125G>A), E709Q(c.2125G>C), E709V(c.2126A>C, G719A(c.2156G>C), G719C(c.2155G>T), G719D(2156G>A), and  G719S(2155G>A); Exon19: K745_E749delKELRE(c.2233_2247del15), c.2233_2247del15, E746_E749delELRE(2235_2246del12), E746_A750>IP(2235_2248>AATTC) E746_A750delELREA(c.2235_2249del15), E746_T751>IP(c.2235_2251>AATTC), E746_T751>I(c.2235_2252>AAT), E746_S752>I(c.2235_2255>AAT), E746_A750>RP(c.2236_2248>AGAC), E746_A750>QP(c.2236_2248>CAAC), E746_A750delELREA(c.2236_2250del15), E746_T751delELREAT(c.2236_2253del18),  E746_S752delELREATS(c.2236_2256del21), E746_T751>A(c.2237_2251del15), E746_T751>VP(c.2237_2251>TTC), E746_T751>V(c.2237_2253>TC), E746_T751>VP(c.2237_2253>TTCCT), E746_T751>VA(c.2237_2253>TTGCT), p.E746_S752>A(c.2237_2254del18), E746_S752>V(c.2237_2255>T, c.2237_2256>TC, and c.2237_2256>TT), E746_P753>VS(c.2237_2257>TCT), L747_A750>P(c.2238_2248>GC), L747_T751>Q(c.2238_2252>GCA), L747_T751delLREAT(c.2238_2252del15), E746_S752>D(c.2238_2255del18), L747_E749delLRE(c.2239_2247delTTAAGAGAA), L747_A750>P(c.2239_2248TTAAGAGAAG>C), L747_T751>P(c.2239_2251>C), L747_T751>Q(c.2239_2252>CA), L747_T751delLREAT(c.2239_2253del15), L747_S752>Q(c.2239_2256>CAA), L747_S752delLREATS(c.2239_2256del18), L747_P753>S(c.2239_2257>T), L747_P753>Q(c.2239_2258>CA), L747_K754delLREATSPK(c.2239_2262del24), L747_T751>S(c.2240_2251del12), L747_T751delLREAT(c.2240_2254del15), L747_P753>S(c.2240_2257del18), A750_K754del(2246_2260del15), A750_E758>P(c.2248_2273>CC), T751_E758delTSPKANKE(c.2252_2275del24), T751_I759>N(c.2252_2276>A and c.2252_2277>AT), S752_I759delSPKANKEI(c.2253_2276del24 and c.2254_2277del24);
Exon 20: T790M(2369C>T), S768I(2303G>T), Exon 20 ins9 (p.V769_D770insASV; c.2307_2308insGCCAGCGTG), Exon 20 insGGT (p.D770_N771insG; c.2310_2311insGGT), Exon 20 ins CAC(p.H773_V774insH; c.2319_2320insCAC); Exon 21: L858M(c.2572C>A), L858R(2573T>G), L861Q(2582T>A), L861R(c.2582T>G).

This test detects EGFR mutations with a sensitivity of 1% in a background of wild type alleles; specific exceptions being: Exon 18 codon 719 (G719S, G719C, G719D and G719) and Exon 18 codon 709 (E709A, E709D, E709G, E709K, E709Q and E709V) which are detected with a sensitivity of 5% in a background of wild-type alleles. Mutation detection sensitivity corresponds to 2% and 10% tumor cells carrying a heterozygous mutation, respectively. This test is validated for use with formalin-fixed paraffin embedded tissue. The test performance has been established with surgical and cytology specimens containing pulmonary adenocarcinoma

Interpretation

--- POSITIVE; EGFR MUTATION(S) DETECTED:
--- NEGATIVE; NO EGFR MUTATION DETECTED.

Clinical Utility

The EGFR Mutation Analysis Assay is intended to assist clinicians in the selection of appropriate systemic therapy for advanced-stage lung adenocarcinoma patients by identifying mutations of EGFR exons 18, 19, 20, and 21 that confer either sensitivity or resistance to select tyrosine kinase inhibitors.

Negative results of this assay are an indication for testing of ALK and ROS1 genes for crizotinib-sensitive gene rearrangements by FISH, since these rearrangements occur in EGFR mutation-negative patients.

EGFR mutations occur in a subset of primary lung adenocarcinomas as well as mixed lung cancers with an adenocarcinoma component. Lung cancers without an adenocarcinoma component, such as pure squamous cell carcinomas, have not been demonstrated to harbor EGFR mutations and should not undergo mutation testing if adequate tumor sampling has been performed. However, mutation testing could be considered in such patients if sampling is limited (e.g. needle core biopsy) and the patient is suspected to have possible adenocarcinoma component.

Per CAP/IASLC/AMP guidelines, EGFR mutation testing should be performed at the time of initial diagnosis for patients with stage IV disease and at the time of recurrence or progression in lower-stage disease if not already done. 

CPT Codes

81235

Contacts

Last Updated

3/22/2021

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