Virtual Library
Start Your Search
Jian-Chun Duan
Author of
-
+
MA06 - PDL1, TMB and DNA Repair (ID 903)
- Event: WCLC 2018
- Type: Mini Oral Abstract Session
- Track: Biology
- Presentations: 1
- Moderators:
- Coordinates: 9/24/2018, 13:30 - 15:00, Room 206 AC
-
+
MA06.07 - Genetic and Epigenetic Alterations are Associated with Tumor Mutation Burden in Non-Small Cell Lung Cancer (ID 12822)
14:10 - 14:15 | Author(s): Jian-Chun Duan
- Abstract
- Presentation
Background
Although several studies have indicated that tumor mutation burden (TMB) is associated with non-small cell lung cancer (NSCLC) development and clinical efficacy of immune checkpoint inhibitors (CPIs), identification of factors associated with TMB is still a major biological issue. It is well-known that DNA transcription can be regulated through methylation and demethylation, gene silencing caused by DNA hypermethylation is associated with cancer development. However, the relationship between DNA methylation and TMB in NSCLCs remains unclear.
a9ded1e5ce5d75814730bb4caaf49419 Method
The landscape of DNA sequence in Chinese NSCLCs population were surveyed by using whole-exome sequencing (WES) by profiling 178 lung tissues (89 without any systemic anti-cancer therapy tumors and matched normal lung tissues). According to the 104 median-level of TMB in our cohort, high TMB (n=16, 252-465 range mutations per tumor) and low TMB (n=13, 57-79 range mutations per tumor) groups were divded. The NSCLC methylome between high and low TMB was characterized on a genome-wide scale using Illumina Infinium MethylationEPIC arrays combined with the WES data.
4c3880bb027f159e801041b1021e88e8 Result
The results show frequently aberrant DNA methylation, abundant chromosomal amplifications and deletions, and mutational signatures in high TMB lung cancer. Combining with clinical data, cigarette smoking associated with high TMB were observed in our cohort. Cancer-specific epigenetic alterations were observed in 294,141 CpG sites, comprising both tumor hyper- (769,38) and hypo- (217,203) methylation in high TMB lung cancer while none in low. These different methylations sites cover 1232 genes including 25 HOX genes.
8eea62084ca7e541d918e823422bd82e Conclusion
Global DNA hypomethylation and TP53 mutation, associated with increased chromosomal instability, were associated with TMB in NSCLCs.The high TMB NSCLCs are characterized by numerous copy number alterations and aberrantly methylated sites and display distinct mutational signatures. 25 hypermethylated HOX genes can be potentially useful as DNA methylation markers for prediction of TMB level. The results provide insights into the epigenetic impact of TMB, which may contribute to improve precison management of NSCLCs.
6f8b794f3246b0c1e1780bb4d4d5dc53Only Members that have purchased this event or have registered via an access code will be able to view this content. To view this presentation, please login, select "Add to Cart" and proceed to checkout. If you would like to become a member of IASLC, please click here.
-
+
P2.01 - Advanced NSCLC (Not CME Accredited Session) (ID 950)
- Event: WCLC 2018
- Type: Poster Viewing in the Exhibit Hall
- Track:
- Presentations: 1
- Moderators:
- Coordinates: 9/25/2018, 16:45 - 18:00, Exhibit Hall
-
+
P2.01-101 - Dynamic Monitoring of Gene Alterations with ctDNA by NGS for EGFR Mutated Lung Adenocarcinoma Treated with Gefitinib in BENEFIT Study (CTONG 1405) (ID 14347)
16:45 - 18:00 | Author(s): Jian-Chun Duan
- Abstract
Background
Blood-based cell-free tumor DNA (ctDNA) could be dynamically monitored to provide gene alterations during EGFR-TKI treatment, which might offer critical clue for prognosis and clinical treatment decision. Here we reported the dynamic gene alterations monitoring using next generation sequencing (NGS) in BENEFIT study to explore the mechanisms of different responses and resistances to EGFR-TKI in EGFR-sensitizing-mutated lung-adenocarcinoma (LADC) patients.
a9ded1e5ce5d75814730bb4caaf49419 Method
Patients with systemic treatment-naïve, stage IV LADC and EGFR-sensitizing-mutation in ctDNA were enrolled to receive gefitinib. Blood samples were dynamically obtained at baseline, every 8 weeks and at disease progression (PD). The dynamic analysis of quantity of ctDNA, multiple driver genes and tumor suppressors were investigated with NGS (Nextseq500 sequencer, consisting of critical exons/introns of 168 genes), and were correlated with efficacy and resistance.
4c3880bb027f159e801041b1021e88e8 Result
Totally 181 LADC patients with EGFR-sensitizing-mutation (exon-19-deletion and exon-21-L858R-point-mutation) provided sufficient blood samples for NGS analysis at baseline, of which 143 patients obtained at least four timepoints of dynamic blood sample collection until PD (baseline, 8 weeks, 8 weeks before PD and PD). At baseline, 180 of patients (99.4%) were confirmed as EGFR-sensitizing-mutation with NGS (92 EGFR-19-deletion and 88 EGFR-L858R-point-mutation) including 44 (24.3%) EGFR-amplification, 116 (64%) TP53-mutation, or other known oncogenic drivers including MET (N=5, 2.8%), ERBB2 (N=7,3.9%), KRAS (N=6, 3.3%), BRAF (N=2, 1.2%), RET (N=1, 0.6%), ROS1 (N=1, 0.6%), or EGFR-T790M (N=4, 2.2%), which was correlated with poor efficacy compared with those with only EGFR-sensitizing-mutation (PFS 4.7 months [m] vs. 13.2m , p=0.002). Additionally, tumor suppressor genes exhibiting cumulative effect to poor prognosis: PFS for 164 patients with TP53&RB1&PTEN-mutation≤1 was 11.1m, while for 16 patients with TP53&RB1&PTEN-mutation＞1，PFS was 4.7 m, p<0.0001. To cut-off date, 117 patients had PD, among them, 63 (54%) patients acquired EGFR-T790M-mutation presented as dominant resistance mechanism besides MET-amplification/ERBB2-amplification/ERBB2-S310F (N=16, 14%), RET fusion/splice (N=2, 1.7%), ROS1-C2336F-mutation (N=1, 0.9%), RB1-nonsense-mutation (N=2, 1.7%), TP53-Y205S-mutation (N=1, 0.9%) and TP53-Y205S-mutation accompanied with FGFR1-amplification (N=1, 0.9%). The remaining resistance mechanisms (31%) were unknown. Patients with only T790M-mutation had a significantly longer PFS (11.5m) compared with patients obtaining other acquired resistant mechanisms (3.0m). Interestingly, seventy-five (53.2%) patients had molecular progression before radiographic progression, and the median time difference was 8.7 weeks.
8eea62084ca7e541d918e823422bd82e Conclusion
Dynamic alterations of multi-drivers and suppressors together with EGFR-sensitizing-mutation and T790M-mutation could separate LADC into different subgroups with distinguished molecular features, which may play a vital role during EGFR-TKI treatment for resistance-predicting, and initial/subsequent treatment decision-making.
6f8b794f3246b0c1e1780bb4d4d5dc53
