Background: Somatic mutations in the epidermal growth factor receptor (EGFR) gene are associated with the responses to the tyrosine kinase inhibitors gefitinib and erlotinib in patients with non-small-cell lung cancer (NSCLC). Although various methods for detecting EGFR gene mutations have been developed, they have several disadvantages. We attempted to establish a new method for the detection of EGFR gene mutations with the use of paraffin-embedded samples.
Methods: The detections of T790M mutations in exon 20 and L858R mutations in exon 21 are based on the principle of allele-specific oligonucleotide polymerase chain reaction (PCR). We also designed PCR primers that enable to detect all types of deletions in exon 19. We assessed the basic performance efficiency of this method, and to confirm its clinical applicability, we performed PCR using DNA extracted from 66 tissue sections that were obtained from patients with NSCLC and embedded in paraffin.
Results: The sensitivity of this method for the detection of deletions or mutations was as low as 0.5%. In the 66 subjects whose samples were analyzed, we detected the following deletions and mutations in the EGFR gene: 11 deletions in exon 19, 8 L858R mutations, and 1 double mutation of L858R and T790M.
Conclusion: The present method is sensitive and specific for the detection of deletions and mutations in the EGFR gene and is thus suitable for use in laboratory tests.