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kaiyan Chen
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P1.01 - Advanced NSCLC (ID 158)
- Event: WCLC 2019
- Type: Poster Viewing in the Exhibit Hall
- Track: Advanced NSCLC
- Presentations: 1
- Moderators:
- Coordinates: 9/08/2019, 09:45 - 18:00, Exhibit Hall
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P1.01-18 - Integrated Genomic and DNA Methylation Analyses of Non-Small Cell Lung Cancer Patients with Brain Metastases (ID 1570)
09:45 - 18:00 | Author(s): kaiyan Chen
- Abstract
Background
Brain metastases (BM), with a dismal prognosis, are a common and lethal complication of non-small cell lung cancer. Approximately, 10% patients present with BM at their initial diagnosis. Although, surgery and/or radiation therapy remain to be the mainstay treatment, targeted therapies are finding increasing application in treating BM. However, due to the very limited accessibility of brain lesions, its genomic and epigenomic landscape remain elusive.
Method
Capture-based targeted sequencing for somatic mutation profiling was performed on 27 treatment-naïve advanced NSCLC patients with paired lung primary and BM lesions using a pane consisting of 520 cancer related genes. DNA methylation analyses was performed on same samples using a DNA methylation panel consisting of 100,000 CpG sites.
Result
Collectively, we identified 370 (291 SNVs+Indels, 78 CNVs and 1 rearrangement) and 574 (245 SNVs+Indels, 327 CNVs and 2 rearrangements) mutations from lung primary lesions and BM, respectively. Among them, 242 mutations were shared; 128 were lung primary-specific and 332 were BM-specific. Among the BM specific mutations, a majority of them (82%, 272/332) were copy number variations (CNVs). Only 16% of CNVs were shared by lung lesions and BM. The concordance for SNVs and indels were much higher-54% between the two sources of tissues. Furthermore, we observed a much higher concordance rate (79%) in TP53 and classic lung cancer driver genes than other genes (p<0.001), indicating that they might be stem mutations. Next, we performed pathway analysis of genes that were only mutated in BM and revealed an enrichment of genes participating in PI3K-AKT and focal adhesion pathways. We also compared tumor mutation burden (TMB) between them and revealed comparable TMB (p=0.1). Our DNA methylation analysis revealed distinct methylation patterns with 268 blocks that are significantly differentially methylated between primary lung lesions and BM. Among them, 211 blocks were hypermethylated in BM and the remaining 57 blocks were hypermethylated in lung lesions. These blocks were enrichment in genes participating in cell adhesion, Rap1 signaling and calcium signaling pathways.
Conclusion
We revealed diverse somatic mutation and DNA methylation profiles between lung primary lesions and BM. BM had significantly more unique CNVs. A great concordance was observed for classic lung cancer driver genes and TP53. Our study provided a comprehensive view of genomic and DNA methylation profiling for lung primary lesions and BM, paving the avenue for the development of targeted therapies for treating BM.
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P2.04 - Immuno-oncology (ID 167)
- Event: WCLC 2019
- Type: Poster Viewing in the Exhibit Hall
- Track: Immuno-oncology
- Presentations: 1
- Now Available
- Moderators:
- Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall
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P2.04-94 - PD-L1 Expression in Uncommon EGFR-Mutant Non-Small Cell Lung Cancer and Its Response to Immunotherapy (Now Available) (ID 300)
10:15 - 18:15 | Author(s): kaiyan Chen
- Abstract
Background
The efficacy of immunotherapy treating EGFR-positive non-small cell lung cancer (NSCLC) patients has been proved to be limited. However, a series of mutant-patients could be benefit from PD-1 blockade. Therefore, this study evaluated the immune microenvironment in NSCLC with uncommon EGFR mutation, and explored the prospect of immunotherapy in this cohort.
Method
We retrospectively evaluated the expression of PD-L1, CD4 and CD8 in NSCLC patients who harbored uncommon EGFR mutation at Zhejiang Cancer Hospital between April 2016 and September 2017. The association with clinical factors and outcomes were also explored, as well as the effectiveness of immunotherapy in uncommon mutation-positive cases.
Result
Among the 600 NSCLC patients with EGFR mutation, we retrospectively collected 49 (8.2%) cases bearing uncommon mutation. In total, 49.0% (24/49) of NSCLC patients showed a strong PD-L1 expression in tumor cells, which was significantly higher than common sensitive (19del and L858R) or negative EGFR mutation (49.0% vs 12.1% vs 26.3%, respectively, P<0.05). Furthermore, positive PD-L1 expression was associated with a significantly shortened OS when compared with the negative PD-L1 expression (20.0 vs 44.3 months, P=0.006). And PD-L1 positivity was predominantly observed among patients with high CD8 expression rather than low cases (72.0% vs 25.0%, P=0.001). Notably, we found PD-L1 and CD8 dual-positive cases demonstrated the worst prognosis (OS: 19.3[dual-positive] vs 31.1[single-positive] vs 44.3[dual-negative] months, P=0.023). Additionally, this approach revealed PD-L1 and CD8 positivity were not associated with the response to EGFR-TKIs, playing no role in the de novo resistance of EGFR-TKIs among the uncommon mutated patients. Finally, one patient harboring EGFR G719A mutation with PD-L1 and CD8 dual positivity experienced a favorable response to anti-PD-1 therapy.
Conclusion
This study revealed the expression of PD-L1, CD4 and CD8 in uncommon EGFR-mutated NSCLC patients. The findings indicated the reshaping of an inflamed immune phenotype characterized by PD-L1 and CD8 dual positivity and suggest potential therapeutic sensitivity to PD-1 blockade.
