EGFR Gene Mutation and Methodological Evaluation in 399 Patients with Non-small Cell Lung Cancer

The purpose of the present study was to study the characteristics of epidemic growth factor receptor (EGFR) gene distribution in patients with non-small cell lung cancer (NSCLC), and to detect the mutation rate of EGFR gene by Sanger sequencing and amplification refractory mutation system (ARMS)-PCR. Paraffin-embedded sections of NSCLC tissues from 399 NSCLC patients diagnosed in Renmin Hospital of Wuhan University were collected, 103 of them were detected for exons 18-21 mutation of EGFR by Sanger sequencing method, 296 cases were detected for exons 18-21 mutation by ARMS-PCR method. DNA extraction of both groups was performed with Qiagen QLAamp DNA FFPE Tissue KIT. Comparisons of detection rates between the two methods were conducted by row X list chi-square test. The total mutation rate of EGFR gene detected by Sanger sequencing was 21.4%, exons 18-21 and combined mutation rates were 1.0%, 9.7%, 1.0%, 7.8% and 2.0%, respectively. And the proportions were 4.7%, 45.2%, 4.7%, 36.3% and 9.4% respectively. The total mutation rate detected by ARMS-PCR was 51.4%, exons 18-21 and combined mutation rates were 2.7%, 27%, 1.7%, 18.2% and 1.7%, respectively. The proportions were 5.3%, 52.6%, 3.3%, 35.5% and 3.3% respectively. Further analysis of mutation rate showed that there was significant difference between the two methods in detecting total mutation of EGFR gene (P<0.001). There were significant differences in mutation detection rates of exons 19 and 21 (P<0.001, P<0.05), but there were no significant differences in other exons. And there was no significant difference in mutation detection rates between the two methods. The mutation rate of EGFR gene in NSCLC patients was 50%. And exon 19 deletion was the most common mutation type, followed by exon 21 mutation. Compared with Sanger sequencing method, ARMS method is more sensitive with significant advantages in detecting exon 19 deletions and exon 21 mutations, which can be widely used in clinical detection of EGFR gene mutations. The results of this study will further guide patients with advanced NSCLC to select TKI targeted drugs, and provide clinical diagnostic basis for targeted therapy of NSCLC patients.