biostudies-literatureUnknown10(3)Silveira C<h4>Background</h4>Liquid biopsy allows the identification of targetable cancer mutations in a minimally invasive manner. In patients with advanced non-small cell lung cancer (NSCLC), droplet digital PCR (ddPCR) is increasingly used to genotype the epidermal growth factor receptor (<i>EGFR</i>) gene in circulating cell-free DNA (cfDNA). However, the sensitivity of this method is still under debate. The aim of this study was to implement and assess the performance of a ddPCR assay for detecting the <i>EGFR</i> T790M mutation in liquid biopsies.<h4>Methods</h4>A ddPCR assay was optimized to detect the <i>EGFR</i> T790M mutation in plasma samples from 77 patients with NSCLC in progression.<h4>Results</h4>Our ddPCR assay enabled the detection and quantification of the <i>EGFR</i> T790M mutation at cfDNA allele frequency as low as 0.5%. The mutation was detected in 40 plasma samples, corresponding to a positivity rate of 52%. The number of mutant molecules per mL of plasma ranged from 1 to 6,000. A re-biopsy was analyzed for 12 patients that had a negative plasma test and the mutation was detected in 2 cases. A second liquid biopsy was performed for 6 patients and the mutation was detected in 3 cases.<h4>Conclusions</h4>This study highlights the value of ddPCR to detect and quantify the <i>EGFR</i> T790M mutation in liquid biopsies in a real-world clinical setting. Our results suggest that repeated ddPCR tests in cfDNA may obviate tissue re-biopsy in patients unable to provide a tumor tissue sample suitable for molecular analysis.Translational lung cancer research1200-1208https://www.ebi.ac.uk/biostudies/studies/S-EPMC8044487biostudies-literatureDetection and quantification of <i>EGFR</i> T790M mutation in liquid biopsies by droplet digital PCR.PMC8044487Pantarotto MSilveira CBrysch ESousa ACJaneiro ABruges-Armas JMalveiro SMadureira RCanario DCarmo-Fonseca MTeixeira EGuimaraes CFelizardo MMatos CNogueira FfalseDetection and quantification of <i>EGFR</i> T790M mutation in liquid biopsies by droplet digital PCR.<h4>Background</h4>Liquid biopsy allows the identification of targetable cancer mutations in a minimally invasive manner. In patients with advanced non-small cell lung cancer (NSCLC), droplet digital PCR (ddPCR) is increasingly used to genotype the epidermal growth factor receptor (<i>EGFR</i>) gene in circulating cell-free DNA (cfDNA). However, the sensitivity of this method is still under debate. The aim of this study was to implement and assess the performance of a ddPCR assay for detecting the <i>EGFR</i> T790M mutation in liquid biopsies.<h4>Methods</h4>A ddPCR assay was optimized to detect the <i>EGFR</i> T790M mutation in plasma samples from 77 patients with NSCLC in progression.<h4>Results</h4>Our ddPCR assay enabled the detection and quantification of the <i>EGFR</i> T790M mutation at cfDNA allele frequency as low as 0.5%. The mutation was detected in 40 plasma samples, corresponding to a positivity rate of 52%. The number of mutant molecules per mL of plasma ranged from 1 to 6,000. A re-biopsy was analyzed for 12 patients that had a negative plasma test and the mutation was detected in 2 cases. A second liquid biopsy was performed for 6 patients and the mutation was detected in 3 cases.<h4>Conclusions</h4>This study highlights the value of ddPCR to detect and quantify the <i>EGFR</i> T790M mutation in liquid biopsies in a real-world clinical setting. Our results suggest that repeated ddPCR tests in cfDNA may obviate tissue re-biopsy in patients unable to provide a tumor tissue sample suitable for molecular analysis.2021-01-01T00:00:00Z2021 Mar2025-04-04T21:24:57.295Z2025-04-04T21:24:57.295ZS-EPMC80444873388950210.21037/tlcr-20-1010