A novel loop-mediated isothermal amplification method for efficient and robust detection of EGFR mutations

Horiuchi, Sho; Saito, Yuichi; Matsui, Atsuka; Takahashi, Nobumasa; Ikeya, Tomohiko; Hoshi, Eishin; Shimizu, Yoshihiko; Yasuda, Masanori

The sensitivity, specificity, PPV, NPV and accuracy values of LAMP for EGFR mutations compared with the Therascreen assay method were 97, 100, 100, 96.3 and 98.3%, respectively, demonstrating the potential of LAMP as an efficient alternative approach t oncogene mutation analyses. To evaluate the sensitivity of these two assays, a genetic analysis was performed to investigate the minimum concentration of EGFR mutation detection in both methods. The minimum concentration for LAMP was 4.8% and there were no detection under 1.0% in the Therascreen assay. Therefore, the minimum concentration for the LAMP assay is ~50 times higher than 4.8% in the Therascreen assay. With almost equal efficiency, detection of the exon 19 mutation in Case X using the Therascreen method suggested that LAMP, as well as direct sequence methods, could identify false negatives. However, additional experiments investigating Case X tumor tissues demonstrated the presence of deletion mutations in exon 19. The direct sequence method has reported low sensitivity (31, 32) , whereas the Therascreen method was generally recognized as a promising method (11, 12) . However, the identified mutation should be simplified, and an improved, faster and cheaper method of identification should be developed for its clinical application.