Highly sensitive and noninvasive detection of epidermal growth factor receptor T790M mutation in non-small cell lung cancer

Abstract

BackgroundEpidermal growth factor receptor (EGFR) T790M mutation is associated with EGFR tyrosine kinase inhibitors resistance in non-small cell lung cancer (NSCLC). However, the tissue availability and technical feasibility limits the genotyping of EGFR T790M mutation in the clinical setting. The current study is, therefore, designed to develop a blood-based approach to detect the EGFR T790M mutation in advanced NSCLC patients. MethodsThe detection of EGFR T790M mutation is based on the principle of mutant-enriched PCR. We assessed the basic performance efficiency of this method, and confirmed its clinical applicability. EGFR T790M mutation in the plasma samples obtained from 33 patients with gefitinib-resistant NSCLC was analyzed by the both mutant-enriched PCR and direct sequencing. ResultsThe sensitivity of this method for the detection of EGFR T790M mutation was as low as 0.1%. In the 33 subjects whose samples were analyzed, the mutant-enriched PCR indentified more EGFR T790M mutation than direct sequencing (36.4% vs. 6.1%, P=0.005), and the EGFR T790M mutation was more frequent in patients with EGFR activating mutations than those without EGFR activating mutations (62.5% vs. 11.8%, P=0.004). Patients with EGFR T790M mutation have a better prior efficacy of gefitinib compared to those without EGFR T790M mutation due to the occurrence of the EGFR activating mutations. ConclusionThe blood-based mutant-enriched PCR is an ideal noninvasive monitoring system for detecting EGFR T790M mutation for clinical application.