Test Directory
EGFR mutation analysis (blood)
Containers - Adult
Roche Diagnostics cell-free DNA collection tube
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Volume Range
2 x 8.5ml |
Laboratory Site
Old Dalkeith Road
Edinburgh
EH16 4SA
Transport arrangements
Referral specimens should be sent directly to Molecular Pathology at the above address (see transport recommendations). Please be aware that blood samples for cfDNA analysis must not be refrigerated and that any tube other than those specified above cannot be accepted for analysis.
Appropriate tubes, request forms and instructions for collection are available on request.
How to request
All requestors, both internal and external to NHS Lothian, will need to provide a completed request form for cfDNA analysis.
Please note that this test is primarily for EGFR mutation analysis for confirmation of TKI resistance mutations but may also be requested where biopsy is not possible. For EGFR mutation analysis for stratification of patients for first line EGFR tyrosine kinase inhibitor therapy, please see EGFR mutation analysis (FFPE).
Availability
Monday - Friday. 09:00 – 17:00
Anticipated turnaround
An integrated Molecular Pathology report should be available within 5 working days. See results.
Static information/disclaimer
This test is accredited to ISO 15189:2012
Please note, alternative methodologies may be used. Full details will be included in all reports.
General additional information
Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) are currently used as first line treatment for patients with advanced metastatic non-small cell lung cancer (NSCLC). Somatic mutations in exons 18 to 21 of the EGFR gene are used to predict response to EGFR TKI therapy.
Often following a period of EGFR TKI therapy, patients will relapse as a result of emergence of mutations conferring resistance, in particular a c.2369C>T p.T790M mutation in exon 20 of the EGFR gene. Patients whose tumours harbour this T790M mutation are eligible for treatment with the third-generation TKI osimertinib and a change in therapeutic strategy may be indicated. Although biopsy remains the preferred material for EGFR mutation analysis, it is possible to detect mutations in cell-free tumour DNA (cfDNA) extracted from peripheral blood; but with reduced sensitivity. Due to the lower sensitivity a negative result cannot exclude the presence of a mutation and a biopsy is strongly recommended if clinically appropriate.
Molecular Pathology use the COBAS® EGFR mutation kit (Roche Diagnostics), which can detect 41 mutations in exons 18-21 of the EGFR gene: 30 deletions and complex mutations in exon 19; c.2369C>T p.(Thr790Met); c.2303G>T p.(Ser768Ile); c.2573T>G or c.2573_2574delTGinsGT p.(Leu858Arg); c.2155G>A p.(Gly719Ser); c.2156G>C p.(Gly719Ala); c.2155G>T p.(Gly719Cys); and 4 insertions in exon 20. The assay detects 86.7% of known mutations in exons 18 to 21 as listed in the Catalogue of Somatic Mutations in Cancer.
EGFR mutation analysis (of FFPE tissue samples) is also carried out as part of the lung cancer testing panel, which also includes KRAS mutation analysis, PD-L1 expression and detection of ALK and ROS1 gene rearrangements.