Simple and sensitive method for detecting point mutations of epidermal growth factor receptor using cationic conjugated polymers.

The L858R mutation of epidermal growth factor receptor (EGFR) in nonsmall cell lung cancer is associated with the increased sensitivity to EGFR tyrosine kinase inhibitors. In this paper, a simple and sensitive method for identification of L858R mutation in cell lines and tumor tissues was developed using cationic conjugated polymer-based fluorescence resonance energy transfer technology (CCP-based FRET). The new detection system can detect even as low as 4-8% mutation of the total DNA. Through the detection results for 48 DNA samples from tumor tissues, a sensitivity of 95.24% (20/21) and a specificity of 96.30% (26/27) were demonstrated. Further, the application of this method in clinical molecular diagnosis was validated by detecting T790 M in EGFR of 35 patients. In comparison with DNA sequencing and real-time PCR methods, our new protocol simplifies procedures by eliminating the need for primer labeling, cumbersome workups and sophisticated instruments and improves sensitivity by amplifying fluorescence signals. Our CCP-based FRET technology is particularly attractive because of its higher sensitivity, cost-effective, and simple characteristics. Particularly, this new method could confirm the suspected positive samples arisen by DNA sequencing and real-time PCR methods. Thus, the CCP-based FRET technology opens up an avenue for clinical therapy by guiding medication to lung cancer patients responsive to anti-EGFR therapy.