Detection Of EGFR Mutations In Plasma CfDNA Of Non-small Cell Lung Cancer By DdPCR And Its Correlation With TKIs

Purpose: This experiment is intended to verify ddPCR method to detect EGFR mutations in non-small cell lung cancer with plasma cfDNA and organizations to adopt the second generation sequencing(Next generation sequencing NGS)results,consistency,and analysis of EGFR gene mutation and clinical pathological relationship,EGFR gene mutation abundance and clinical features between contact and EGFR gene mutation and clinical application of TKIs correlation analysis of curative effect.Methods: Samples of patients with non-small cell lung cancer from nanhua hospital affiliated to nanhua university and the first affiliated hospital of nanhua university from August 2016 to December 2018 were collected and included in the experimental group.After obtaining the consent of the patients and signing the informed consent,their blood and tissue sections were obtained for gene sequencing examination.ddPCR was used to detect the common mutation sites of EGFR gene,namely the mutations of exons 18,19 and 21.Results:(1)EGFR gene mutation was successfully detected in tumor tissues of 190 patients with NSCLC,and there was no significant difference in EGFR mutation abundance,gender or smoking history.There were statistically significant differences between EGFR mutation abundance and pathological typing.EGFR gene mutation abundance was significantly higher in adenocarcinoma patients than in non-adenocarcinoma patients.(2)among the 190 patients,72 patients were positive for tissue EGFR mutation,including 44 cases of Exon21 L858R(3 case with T790 M mutation)and 28 cases of Exon19 del(1 case with T790 M mutation).56 patients were positive for EGFR mutation in plasma cfDNA,including 32 cases of Exon21 L858 R and 24 cases of Exon19 del.The sensitivity and specificity of plasma EGFR mutation were 69.4% and 94.9%.Patients with positive tissue EGFR mutations were given EGFRTKIs for a median PFS of 328 days(95% CI,288.610-367.390),the median PFS in patients with negative tissue mutations was 146 days(95% CI,107.672-184.328).There were statistically significant differences between the two groups(P<0.05).suggesting that EGFR-TKIs therapy was effective.Conclusion: In lung adenocarcinoma,EGFR gene mutation abundance was not significantly correlated with age,gender,tumor stage and smoking history.The detection of plasma cfDNA mutation by ddPCR has high sensitivity and specificity,which can provide reliable data for the use of targeted drugs.