Mutation Characteristics Of CtDNA In Non-small-cell Lung Cancer Common Genes And Its Clinical Practice

Objective: To investigate the ctDNA of peripheral blood by NGS method to understand the cancer gene map of lung cancer patients and to guide the clinical treatment by monitoring ctDNA changes before and after drug resistance,and to further explore the mechanisms of drug resistances.Methods: 1.Case collectionCollected 69 cases non-surgical local advanced or advanced lung cancer patients from March 2016 to October 2016 in three hospitals of Fuzhou.2.Detection of ctDNACollect blood samples from peripheral blood,extract blood free DNA,construct DNA library,carry out sequencing and capture DNA,and send the DNA library to Shenzhen Haplox Biotechnology Co.LTD for sequence analysis.3.Bioinformatics analysis Extraction of base information,data quality control,access to variation information,analysis Results:A total of 313 mutations were detected in 59 patients with squamous cell carcinoma and adenocarcinoma.About 5.3 mutations were detected in each patient.Most of the mutations were missense mutations.The higher mutation rates in 69 patients were ATM,TRRAP,MTOR,TP53,TOP2 A,BRAF,RET,TSC2,FCT3 and CDKN2 A,the mutation frequencies are 35%,30%,30%,28%,22%,22%,20%,19%,17%,16% respectively.The higher mutation rates in 49 adenocarcinoma patients were ATM,MTOR,TRRAP,BRAF,APC,TP53,TSC2,TOP2 A,TYMP and XPC,the mutation frequencies were as follows: 34%,30%,28%,24%,24% %,22%,22%,16%,16%,16%.The higher mutation rates in 10 squamous cell carcinoma patients were XRCC1,TP53,RRM1,TOP2 A,TRRAP,ERBB2,CDKN2 A,BRAF,CYP2D6 and BRCA1,the mutation frequencies were as follows : 40%,40%,40%,30%,30%,30%,20%,20%,20%.The frequency of common carcinogens mutations were BRAF(22%)?RET(20%)?ERBB2(16%)?PIK3CA(5%)?KRAS(4%);The frequency of common tumor suppressor gene mutations were: TP53(28%),CDKN2A(16%),PTEN(13%).A total of 23 patients were detected EGFR gene mutations,including: EGFR-19 del 13 cases,EGFR-21L858 r mutation in 5 cases,EGFR: exon18: c.G2155T: p.G719 C + EGFR: exon20: c.G2303T: p.S768 I 1 case of EGFR-19 del + EGFR T790 M mutation,1 case of EGFR-21 L858 r + EGFR T790 M mutation,1 case of KRAS: exon2: c.G34T: p.G12 C mutation,PIK3CA: exon10: c.G1624A: p.E542 K mutation in 1 case.Compared with the application of ARMS method,NGS method to detect peripheral blood ctDNA of NSCLC EGFR gene mutation sensitivity specificity were 56.5%? 70% Respectively,Consistent rate of 91%.Till 2017-1,16 patients with EGFR-TKI targeted therapy,9 patients can assess PFS,of which: 5 patients with PFS> 5 months,2 cases of PFS <2 months,consider the P53,NOTCH1 gene Mutant patients may predict adverse effects.Conclusions: 1)Using the Shenzhen Haplox Biotechnology Co.LTD gene panel detection method to detect the plasma ctDNA is feasible;2)The gene mutations,which are associated with lung cancer,can be detected by NGS and bioinformatics analysis method;3)Dynamic monitoring of plasma ctDNA changes contribute to guide clinical practice and explore drug resistance mechanisms.