A digital PCR assay development to detect EGFR T790M mutation in NSCLC patients

Epidermal growth factor receptor (EGFR) is a crucial factor in the development of non-small cell lung cancer (NSCLC). Tyrosine kinase inhibitor (TKI) therapy requires a sensitive and accurate assay for detection of drug resistant mutations in patients undergoing TKI-based targeted therapy. Digital polymerase chain reaction (PCR) is a highly sensitive PCR based detection method with the capability of absolute quantification. Here we present a digital PCR based liquid biopsy for EGFR T790M detection from blood samples with a low detection limit of 0.1% mutant allele frequency. The assay shows 100% concordance with test results obtained from cFDA approved ARMS PCR based EGFR mutation detection assay on FFPE tissue sections. It also demonstrated satisfactory sensitivity and specificity at 62.5% and 100% respectively. This assay can satisfy the clinical need of detecting EGFR T790M mutations at extremely low allele frequency. It can be used as both a companion diagnostic tool and a monitoring strategy for the development of drug resistance, and to evaluate therapeutic effects on disease progression.