WCLC 2022 | NGS provides improved identification of uncommon EGFR mutations over PCR in NSCLC
Hazel O’Sullivan, MBBS, The Royal Marsden NHS Foundation Trust, London, UK, provides an overview of an investigation into the detectability of uncommon EGFR mutations via frequently used assays. The database of the clinical genomic lab at the Royal Marsden Hospital was retrospectively analyzed to identify EGFR mutations in NSCLC samples with EGFR mutations in exons 18-21. Uncommon mutations were defined as EGFR mutations in exons 18-21 excluding exon 19 deletions, L858R mutations, T790M mutations and EGFR exon 20 insertions. 1463 patient samples underwent next generation sequencing (NGS), 303 were found to have EGFR mutations, 14% of which were uncommon mutations. The ability of frequently used cobas and Idylla PCR assays to detect uncommon EGFR mutations were then evaluated. It was found that 30% of the uncommon EGFR mutations would have been missed by these PCR assays and thus, NGS may be used to substantially improve the identification of these mutations. This interview took place at the IASLC 2022 World Conference on Lung Cancer congress in Vienna, Austria.
Transcript (edited for clarity)
We reviewed the next-generation sequencing database at the Royal Marsden Hospital clinical genomic laboratory. We identified cases with EGFR mutations in exons 18 to 21, and we defined uncommon EGFR mutations as EGFR mutations in exons 18 to 21, excluding exon 19 deletions, L858R mutations, T790M mutations and EGFR exon 20 insertions. Between February 2020 and September 2021, 1,463 patients under our next generation sequencing at our institution and 303 cases had EGFR mutations, 14% of these were uncommon mutations...
We reviewed the next-generation sequencing database at the Royal Marsden Hospital clinical genomic laboratory. We identified cases with EGFR mutations in exons 18 to 21, and we defined uncommon EGFR mutations as EGFR mutations in exons 18 to 21, excluding exon 19 deletions, L858R mutations, T790M mutations and EGFR exon 20 insertions. Between February 2020 and September 2021, 1,463 patients under our next generation sequencing at our institution and 303 cases had EGFR mutations, 14% of these were uncommon mutations. We then assessed the frequently used assays EGFR, and cobas, PCR assays, to assess what proportion of these uncommon mutations would be detectable with these frequently used assays. We found that EGFR and cobas would’ve missed 30% of the uncommon mutations detected in our population.
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