RESUMO
BACKGROUND: The non-invasive identification of epidermal growth factor receptor (EGFR) mutations is important for the institution of individualized therapy of non-small cell lung cancer (NSCLC). In this study, the feasibility of screening for EGFR exon 19 E746_A750del mutations in circulating DNA from plasma was assessed. METHODS: Mutant-specific primers with a Taqman probe (MST-PCR) were designed. The ability of this method to accurately detect decreasing concentrations of E746_A750del mutant within a wild type DNA background that mimics the situation of a plasma sample from patients with acquired mutations is verified. To verify the clinical applicability of this method, 55 plasma samples from NSCLC patients were tested, and the sensitivity of MST-PCR was compared to that of direct sequencing. RESULTS: The results showed that MST-PCR could detect 10 to 50 copies/microL of E746_A750del, representing 0.1% of the wild type EGFR allelic population. Among the 55 cases of NSCLC, 10 cases of E746_A750del were detected by MST-PCR, while only 1 case was revealed by direct sequencing. CONCLUSIONS: These findings demonstrate that MST-PCR provides superior sensitivity for the detection of the E746_A750del mutation, suggesting its potential application in the noninvasive detection of E746_A750del mutations in plasma samples from NSCLC patients.
