Clinical Study On Real-time Sequencing Of Tumor In-situ Fluid To Dynamically Track Glioma Evolution

ObjectiveTo explore the clinical significance of real-time sequencing of Tumor in-situ fluid(TISF)DNA in monitoring the postoperative evolution of glioma.MethodsFrom March 2018 to December 2020,32 patients with glioma were treated in People’s Hospital of Zhengzhou University.Precise imaging diagnosis was performed preoperatively,accurate neurosurgery was performed,and the tumor was removed safely to the maximum extent.The fluid storage sac was implanted at the time of surgery to obtain TISF.Tumor tissue samples of the patients were obtained during the operation,Cerebrospinal fluid samples,TISF samples and blood samples were obtained after the operation.The tissue samples,Cerebrospinal fluid samples,and TISF samples were detected for tumor DNA mutation by next generation sequencing(NGS),and the blood samples were tested for leukocyte germ line mutation,and the tumor mutation genes were screened by comparison.Combined with the clinical data,the tumor DNA test results among different samples of patients were compared and bioinformatics analysis was conducted to evaluate the postoperative evolution of glioma patients.Results1.Tumor DNA mutations were detected in 93.7%(30/32)of the tumor tissues.In TISF,the positive rate of early postoperative detection(TISF-1)was 93.3%(28/30),and the positive rate of glioma progression(TISF-2)was 100.0%(30/30),and abundant tumor DNA was found.2.The coincidence rate of mutations between the relapsed tumor and the primary tumor detected by TISF was low,only 45.8%.Longitudinal analysis of tumor genome spectrum could detect the spatio-temporal heterogeneity evolution of glioma.3.TISF-DNA has a higher positive rate than CSF-ct DNA,and contains more representative tumor DNA,which can truly reflect tumor evolution.4.Tumor progression is accompanied by an increase in cf DNA concentration in TISF(P<0.0001),a further increase in mutational load(P<0.0001),and an increase in VAF in the trunk mutant gene(P<0.0001).5.High concentration of cf DNA in early postoperative TISF indicates high residual MRD in early postoperative TISF,which is a predictor of early recurrence(less than 180days)Independent risk factors(OR=1.667,95%CL,1.078-2.576,P=0.021).The cf DNA concentration in TISF-2 was significantly higher in patients with an overall survival(OS)of less than 600 days than in patients with an OS of more than 600 days(P=0.006).Conclusion1.Real-time sequencing of TISF-DNA is a more representative new method for liquid biopsy of glioma,which can be used for genetic diagnosis and dynamic monitoring of glioma.2.Continuous TISF-DNA testing in patients with glioma after surgery can assess minimal residual disease(MRD)and predict the risk of recurrence.3.Real-time sequencing of TISF-DNA can dynamically monitor the genomic information of glioma and provide a basis for personalized targeted therapy of recurrent glioma.