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Z. Dong



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    JCES01 - Joint IASLC - Chinese Society for Clinical Oncology - Chinese Alliance Against Lung Cancer Session (ID 413)

    • Event: WCLC 2016
    • Type: Joint Chinese / English Session
    • Track:
    • Presentations: 2
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      JCES01.18 - Dual Positive PD-L1 and CD8+ TIL Represents a Predominant Subtype in NSCLC and Correlates with Augmented Immunogenicity (ID 7060)

      Z. Dong

      • Abstract
      • Slides

      Background:
      Recent studies have identified that the degree of tumor infiltrating lymphocyte (TIL) infiltration and PD-L1 expression in the tumor microenvironment (TME) are significantly correlated with the clinical outcomes of anti-PD-1/PD-L1 therapies. Here we conducted this study to verify the distribution of PD-L1/CD8[+] TIL expression and its clinical significance in non-small cell carcinoma (NSCLC). Potential mechanism predicted for PD-1 blockade was explored in depth as well.

      Methods:
      Immunohistochemistry was performed to detect PD-L1 and CD8 expression in NSCLC. The Kaplan–Meier (KM) survival curve was used to estimate disease free survival (DFS) and overall survival (OS). Gene Set Enrichment Analysis (GSEA) was used to determine potentially relevant gene expression signatures.

      Results:
      288 cases with stage I-IIIA NSCLC were evaluated for PD-L1 and CD8+ TIL staining. Dual positive PD-L1 and CD8 (PD-L1+/CD8+) represents a predominant subtype in NSCLC, accounting for 36.5% (105/288), followed by PD-L1-/CD8- (24.3%, 70/288), PD-L1-/CD8+ (26.0%, 75/288) and PD-L1+/CD8- (13.2%, 38/288). Survival analysis of DFS (p=0.031) and OS (p=0.002) showed a significant difference between four subgroups. Furthermore, we analyzed the correlation between expression types of PDL1/CD8 and mutation burden and angtigen presentation. We can identified dual positive PD-L1 and CD8 was significant with increased mutation burden (p<0.001), high frequency of mismatch repair (MMR) related gene mutation. More interestingly, tumor with dual positive PD-L1 and CD8 manifested a remarkable activated angtigen presentation and T cell receptor signature compared with other subgroups.

      Conclusion:
      Dual positive PD-L1 and CD8 was identified as a predominant subtype in NSCLC and correlates with increased immunogenicity. These findings provide the evidence that combined analysis of PD-L1 and CD8 in NSCLC may be a promising way to predict PD-1 blockade immunotherapy.

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      JCES01.24 - Molecular Mechanism of Transformation from Adenocarcinoma to Small-Cell Lung Cancer after EGFR-TKI (ID 7066)

      Z. Dong

      • Abstract
      • Slides

      Background:
      In patients with advanced non–small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) activating mutations, EGFR-tyrosine kinase inhibitors (TKIs) are recommended as first-line treatment due to favorable clinical efficacy. However, acquired resistance inevitably develops after median progression-free survival (PFS) of 9-14 months. Among the mechanisms of acquired resistance, small-cell lung cancer (SCLC) transformation was reported to account for nearly 5%. However, the molecular details underlying this histological change and resistance to EGFR-TKI therapy remain unclear.

      Methods:
      15 out of 233 (6.4%) patients were confirmed to develop SCLC transformation after failure to EGFR-TKI. We analyzed the clinical parameters of these patients by using chi-square test and Kaplan-Meier analysis. To explore gene alterations that might contribute to SCLC transformation, next generation sequencing (NGS) was performed on four pairs of matched pre- and post-transformation tumor tissue samples. We further performed NGS on 11 matched circulating tumor DNA (ctDNA) to explore the potential mechanism of resistance to EGFR-TKI.

      Results:
      The median age of SCLC transformed patients was 53 years. 93.3% (14/15) patients harbored EGFR exon19 deletion. The median PFS and overall survival (OS) of SCLC-transformed patients treated with EGFR-TKI compared to those without transformation were 11.7 versus 11.9 months (P=0.473) and 29.4 versus 24.3 months (P=0.664), respectively. All 4 patients developed loss of heterozygosity of TP53/RB1 after transformation. Besides, increased copy number of five proto-oncogenes were identified in post-transformation tissue samples. Three patients developed EGFR T790M mutation in the post-transformation ctDNA rather than their tissue samples.

      Conclusion:
      SCLC transformation was commonly seen in patients harboring EGFR exon 19 deletion. The clinical outcomes of TKI and OS in SCLC transformed patients were similar to non-transformed patients. The loss of heterozygosity of TP53 and RB1along with increased copy number of proto-oncogenes may lead to the SCLC transformation. The mechanisms of acquired resistance to TKI during SCLC transformation might be the emergence of classic drug resistance mutations, which was undetectable due to the intra-tumor heterogeneity.

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    MA15 - Immunotherapy Prediction (ID 400)

    • Event: WCLC 2016
    • Type: Mini Oral Session
    • Track: Chemotherapy/Targeted Therapy/Immunotherapy
    • Presentations: 1
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      MA15.10 - Potential Predictive Value of TP53 and KRAS Mutation Status for Response to PD-1 Blockade Immunotherapy in Lung Adenocarcinoma (ID 4885)

      Z. Dong

      • Abstract
      • Slides

      Background:
      Although clinical studies have shown promise for targeting programmed cell death protein-1 (PD-1) and ligand (PD-L1) signaling in non-small cell lung cancer (NSCLC), the factors that predict which subtype patients will be responsive to checkpoint blockade remains elusive. This study was sought to identify the potential biomarkers that predicted response to PD-1 blockade immunotherapy in lung adenocarcinoma.

      Methods:
      We performed an integrated analysis on the multiple-dimensional data types including genomic, transcriptomic, proteomic and clinical data from cohorts of both lung adenocarcinoma public database including The Cancer Genome Atlas (TCGA), GEO repository (GSE72094) and Broad dataset, and clinical immunotherapeutic patients in our center. Gene Set Enrichment Analysis (GSEA) was used to determine potentially relevant gene expression signatures between specific subgroups.

      Results:
      We observed distinct function of TP53 and KRAS mutation in regulating immune tumor microenvironment (TME). It is TP53 mutation but not KRAS mutation in lung adenocarcinoma that significantly increased expression of immune checkpoints, facilitated CD8+T cell infiltration and activated T-effector and interferon-γ (IFN-γ) signature. Interestingly, TP53 and KRAS co-mutated subgroup manifested exclusive increased expression of PD-L1 and a highest proportion of PD-L1+/CD8A+. More importantly, TP53 or KRAS mutated tumors showed prominently increased mutation burden and specifically enriched in the transversion-high (TH) cohort. Further analysis focused on the potential molecular mechanism revealed that TP53 or KRAS mutation altered a group of genes involved in cell cycle regulating, DNA replication and damage repair. Finally, clinical immunotherapeutic data were further confirmed that TP53 or KRAS mutation lung adenocarcinoma patients, especially those with co-occurring TP53/KRAS mutations, showed remarkable clinical benefit to PD-1 blockade immunotherapy. Figure 1



      Conclusion:
      This work provides evidence that TP53 and KRAS mutation in lung adenocarcinoma may be served as a pair of potential predictive factors in guiding PD-1 blockade immunotherapy.

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    P3.02b - Poster Session with Presenters Present (ID 494)

    • Event: WCLC 2016
    • Type: Poster Presenters Present
    • Track: Advanced NSCLC
    • Presentations: 2
    • Now Available
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      P3.02b-095 - Tracing Spatiotemporal T790M Heterogeneity in Patients with EGFR-Mutant Advanced NSCLC after Acquired Resistance to EGFR TKIs (Now Available) (ID 6057)

      Z. Dong

      • Abstract
      • Slides

      Background:
      With the marketing of osimertinib, epidermal growth factor receptor (EGFR) T790M mutation has become a clinically significant biomarker for advanced EGFR-mutant non-small-cell lung cancer (NSCLC) after acquired resistance to previous EGFR TKIs. However, T790M status might vary spatiotemporally and consequently hinder the initiation and clinical efficacy of third generation EGFR TKIs. Till now, the spatiotemporal traces of T790M under treatment pressure have not been fully elucidated.

      Methods:
      We retrospectively reviewed T790M status and clinical courses of 93 patients who underwent multiple (≥2) rebiopsies after acquired resistance to first or second generation EGFR TKIs from 2010 to 2015 in Guangdong General Hospital. Patients underwent synchronous rebiopsies at the same lesion or paired tissue and plasma rebiopsies were enrolled to evaluate the spatial T790M heterogeneity. Patients received heterochronous rebiopsies at the same lesion or different lesions were enrolled to evaluate the temporal and spatiotemporal T790M heterogeneity respectively.Tissue EGFR detection was performed by SNAPSHOT or Amplification Refractory Mutation System (ARMS). Plasma EGFR was detected by ARMS.

      Results:
      A total of 99 evaluations were performed with 6 of 93 enrolled patients underwent both synchronous and heterochronous rebiopsies. Among 20 patients who underwent synchronous rebiopsies at the same lesion, 13 revealed T790M heterogeneity. Among 17 patients who had paired tissue and plasma rebiopsies, 8 showed T790M heterogeneity. Spatial T790M heterogeneity ratio was 57% (21/37) in general. 33% (10/30) patients who received heterochronous rebiopsies at the same lesion revealed temporal T790M heterogeneity. Spatiotemporal T790M heterogeneity was observed in 53% (17/32) of patients who received heterochronous multiple sites rebiopsies. Of abovementioned patients with heterochronous T790M heterogeneity, T790M status in 67% (18/27) switched from negative to positive after chemotherapy or continuation of EGFR TKIs and in 33% (9/27) switched from positive to negative after chemotherapy or combined regimens of chemotherapy and EGFR TKIs.

      Conclusion:
      T790M status could vary spatiotemporally at a ratio of 33-57% in patients with acquired resistance to previous EGFR TKIs. Repeated rebiopsies both at the same lesion and various lesions might be valued particularly in T790M-negative cases in this subset of patients.

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      P3.02b-116 - Molecular Mechanism of Transformation from Adenocarcinoma to Small-Cell Lung Cancer after EGFR-TKI (Now Available) (ID 4983)

      Z. Dong

      • Abstract
      • Slides

      Background:
      In patients with advanced non–small-cell lung cancer (NSCLC) harboring epidermal growth factor receptor (EGFR) activating mutations, EGFR-tyrosine kinase inhibitors (TKIs) are recommended as first-line treatment due to favorable clinical efficacy. However, acquired resistance inevitably develops after median progression-free survival (PFS) of 9-14 months. Among the mechanisms of acquired resistance, small-cell lung cancer (SCLC) transformation was reported to account for nearly 5%. However, the molecular details underlying this histological change and resistance to EGFR-TKI therapy remain unclear.

      Methods:
      15 out of 233 (6.4%) patients were confirmed to develop SCLC transformation after failure to EGFR-TKI. We analyzed the clinical parameters of these patients by using chi-square test and Kaplan-Meier analysis. To explore gene alterations that might contribute to SCLC transformation, next generation sequencing (NGS) was performed on four pairs of matched pre- and post-transformation tumor tissue samples. We further performed NGS on 11 matched circulating tumor DNA (ctDNA) to explore the potential mechanism of resistance to EGFR-TKI.

      Results:
      The median age of SCLC transformed patients was 53 years. 93.3% (14/15) patients harbored EGFR exon19 deletion. The median PFS and overall survival (OS) of SCLC-transformed patients treated with EGFR-TKI compared to those without transformation were 11.7 versus 11.9 months (P=0.473) and 29.4 versus 24.3 months (P=0.664), respectively. All 4 patients developed loss of heterozygosity of TP53/RB1 after transformation. Besides, increased copy number of five proto-oncogenes were identified in post-transformation tissue samples. Three patients developed EGFR T790M mutation in the post-transformation ctDNA rather than their tissue samples.

      Conclusion:
      SCLC transformation was commonly seen in patients harboring EGFR exon 19 deletion. The clinical outcomes of TKI and OS in SCLC transformed patients were similar to non-transformed patients. The loss of heterozygosity of TP53 and RB1 along with increased copy number of proto-oncogenes may lead to the SCLC transformation. The mechanisms of acquired resistance to TKI during SCLC transformation might be the emergence of classic drug resistance mutations, which was undetectable due to the intra-tumor heterogeneity.

      Only Active 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 or select "Add to Cart" and proceed to checkout.