Assessment of high-sensitive methods for the detection of EGFR mutations in circulating free tumor DNA from NSCLC patients

We assessed the ability of the Therascreen(®) kit (plasma-Therascreen) and of a peptide nucleic acids (PNA)-clamp approach to detect EGFR mutations in plasma-derived circulating-free tumor DNA (cftDNA) from non-small-cell lung cancer patients. cftDNA from 96 patients was analyzed for exon 19 deletions and the p.L858R mutation, using both plasma-Therascreen and PNA-clamp-based assays. None of the 70 EGFR wild-type patients showed EGFR mutations in cftDNA with both techniques (specificity: 100%). In 17/26 EGFR-mutant patients, plasma-Therascreen analysis confirmed the mutation identified in the primary tumor (analytical sensitivity: 65.4%). Similar results were obtained with the PNA-clamp method. Both approaches were specific and sensitive for EGFR mutational analysis of cftDNA in non-small-cell lung cancer patients.