| BACKGROUND:Driver genes play an important role in the development,progression and metastasis of lung cancer.It is also an important predictor of molecular targeted therapy for lung cancer.Many studies have shown that driver genes are involved in the process of cell homing,colonization and the change of tumor microenvironment in the process of lung cancer metastasis.This study mainly discussed the gene mutation heterogeneity of primary and bone metastasis in advanced lung adenocarcinoma,and searched for the key genes of bone metastasis in lung cancer Method:We collected 15 patients diagnosed with lung adenocarcinoma with bone metastasis in the second affiliated hospital of nanchang university from May 2017 to February 2019.Meanwhile,CT-guided fine needle biopsy was performed on the patients' primary lung lesions and matched bone metastasis,and 30 cases of tumor tissues of primary lung lesions and bone metastasis were obtained.CN500 NGS second-generation sequencing platform was used to sequence 398 tumor-related genes in 30 tumor tissue samples to analyze the differences of gene mutations in different lesions.We compared the gene mutation spectrum,mutation rate and mutation abundance of primary lung adenocarcinoma and bone metastasis,and analyzed the differences between primary lung adenocarcinoma and bone metastasis.At the same time,the enrichment analysis of bone metastasis mutant genes was carried out,and the genes affecting bone metastasis of lung adenocarcinoma and the involved signal pathways were analyzed according to the biological function classification.Results:We enrolled 15 patients which have lung cancer bone metastasis,and sequenced30 tumor tissue samples each come from primary lung and matched bone metastasis.Two hundred and twenty somatic gene mutations were detected,including point mutation,insertion,and deletion.In total,there were 63 genes with mutationabundance greater than 5%,42 primary pulmonary foci,46 bone metastases,and 18co-mutated genes(Fig 3).The driver genes with high mutation rate in the total samples are EGFR(14/30),TP53(12/14),ROS1(4/30),APC(3/30),ADGRL3(3/30)and SYNE1(3/30)(Table 1-2).Among all cancer driver genes,the top five gene mutations of EGFR(7/15),TP53(7/15),ROS1(3/15),IDH2(2/15),and SYNE1(2/15)were found to be mutated in lung adenocarcinoma patients(Fig 4A);EGFR(7/15),TP53(5/15),ADGRL3(2/15),APC(2/15)in bone metastasis(Fig 4B).Moreover,according to over 50% mutation frequencies,the top three genes were EGFR(79.03%),ADGRL3(75.25%),and FANCD2(57.81%)in lung adenocarcinoma patients;the top four genes in BM patients were ADGRL3(91.28%),EGFR(72.14%),KEAP1(62.99%),and STK11(55.18%).In addition,gene mutation frequencies of BM patients were higher than lung adenocarcinoma patients in PBRM1(25.51% VS 22.38%),TCF3(15.00% VS 12.38%),PIK3CG(44.74% VS31.14%),ADGRL3(91.16% VS 75.00%)and KEAP1(62.99% VS 20.26%)(Table1-3),respectively.The mutation rates of EGFR,TP53 and EGFR combined TP53 were 46.7%,40% and 33.3%.The consistent mutation rate of EGFR in primary tumors and bone metastases mutation rate was 86.7%(k = 0.732,p = 0.005)(Table1-5),mutation abundance have no difference(p >0.05),there are 5 cases have the same gene mutation site in primary tumors and bone metastases with EGFR mutations(19 del in 2 cases,1 case with L858 R,G719S in 1 case,L861 Q 1 case),1case of mutations in patients with inconsistent(primary focal L858 R mutations,bone metastases 19 del)(Table 1-4).T The consistent mutation rate of TP53 in primary tumors and bone metastases mutation rate was 86.7%(k=0.727,p=0.003),and the mutation abundance have no different(p>0.05).The TP53 mutation sites of primary and bone metastases were consistent in 4 patients(R248W in 2 patients,I232 F in 1patient,E258 D in 1 patient),and the mutation sites were inconsistent in 1 patient(R248Q in primary and I195 S in bone metastases)(table 1-4).The mutation consistency rate of EGFR combined with TP53 was 100%(k=1,p < 0.05)(Table1-5).GO analysis and functional classification were performed on the mutant genes of primary lung cancer and bone metastasis.The genes regulating cell adhesion and movement(ADGRL3,EGFR,PIK3 CG,LPP,SMARCA4,TLR4 and ESR1),regulation of osteoclast differentiation genes(MTOR?KMT2C?KMT2D?TFE3 and CTNNB1)are more enrichment in bone metastases compared with parimary tumor(Fig 6).Conclusion:1.The organ microenvironment of primary lung cancer and bone metastasis is heterogeneous2.EGFR and TP53 mutations are highly consistent in primary lung cancer and bone metastasis,and activation of the EGFR and TP53 signaling pathway may promote bone metastasis in lung cancer patients3.The genes regulating cell adhesion and movement and Regulates osteoclast differentiation more abundant in bone metastases,which may be associated with bone metastasis of lung cancer... |
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