Non-invasive diagnosis of actionable mutations by deep sequencing of circulating-free DNA in non-small cell lung cancer: Findings from BioCAST / IFCT-1002
Menée sur des échantillons plasmatiques prélevés sur 107 patients atteints d'un cancer du poumon métastatique, cette étude évalue la faisabilité et l'intérêt d'une analyse de l'ADN libre circulant pour identifier des mutations de gènes tumoraux susceptibles d'orienter le choix d'une thérapie ciblée
PURPOSE: Tumor somatic mutation analysis is part of the standard management of metastatic lung cancer. However, physicians often have to deal with small biopsies and consequently with challenging mutation testing. Circulating-free DNA (cfDNA) is a promising tool for accessing the tumor genome as a liquid biopsy. Here we evaluated next generation sequencing (NGS) on cfDNA samples obtained from a consecutive series of patients for the screening of a range of clinically relevant mutations.
METHOD: One hundred seven plasma samples were collected from the BioCAST / IFCT-1002 lung cancer study (never-smokers cohort). Matched tumor DNA (tDNA) was obtained for 68 cases. Multiplex PCR-based assays were designed to target specific coding regions in EGFR, KRAS, BRAF, ERBB2 and PI3KCA genes and amplicon sequencing was performed at deep coverage on the cfDNA/tDNA pairs using the NGS IonTorrent PGM Platform.
RESULTS: CfDNA concentration in plasma was significantly associated with both stage and number of metastatic sites. In tDNA, 50 mutations (36 EGFR, 5 ERBB2, 4 KRAS, 3 BRAF, and 2 PIK3CA) were identified, of which 26 were detected in cfDNA. Sensitivity of the test was 58% [95%CI: 43%-71%] and the estimated specificity was 87% [62%-96%].
CONCLUSION: These data demonstrate the feasibility and potential utility of mutation screening in cfDNA using IonTorrent NGS for the detection of a range of tumor biomarkers in patients with metastatic lung cancer.
Clinical Cancer Research , résumé, 2014