Detection of exon 19 deletion mutation in the
epidermal growth factor receptor (EGFR) gene, which results in increased and sustained phosphorylation of EGFR, is important for diagnosis and treatment guidelines in
non-small-cell lung cancer. Here, we have developed a simple and convenient detection system using the interaction between G-quadruplex and fluorophore
thioflavin T (ThT) for discriminating EGFR exon 19 deletion mutant
DNA from wild type without a label and quencher. In the presence of exon 19 deletion mutant
DNA, the probe DNAs annealed to the target sequences were transformed into G-quadruplex structure. Subsequent intercalation of ThT into the G-quadruplex resulted in a light-up fluorescence signal, which reflects the amount of mutant
DNA. Due to stark differences in fluorescence intensity between mutant and wild-type
DNA, we suggest that the induced G-quadruplex structure in the
probe DNA can report the presence of
cancer-causing deletion mutant DNAs with high sensitivity.