Author of

• 30844

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  P1.04 - Immuno-oncology (ID 164)

  • Event: WCLC 2019
  • Type: Poster Viewing in the Exhibit Hall
  • Track: Immuno-oncology
  • Presentations: 2
  • Moderators:
  • Coordinates: 9/08/2019, 09:45 - 18:00, Exhibit Hall

  • 30852

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    P1.04-06 - Tumor Microenvironment Landscape in Lung Adenocarcinoma by Single-Cell Sequencing (ID 1227)

    09:45 - 18:00  |  Presenting Author(s): Bo Mi Ku
    • Abstract

    Background
    

    Lung cancer is the leading cause of cancer cell death in worldwide. Failure of early detection, high recurrence rate and metastasis all contribute to the low survival rate in this detrimental disease. In particular, frequent brain metastasis confers an imperative challenge in the management of lung cancer. Single-cell RNA sequencing provides specific profiling of cell populations at the single-cell level. Interpretation of single-cell transcriptome data for the discovery of therapeutic targets and prognostic biomarkers is an ongoing challenge in precision cancer medicine. Especially, the influence of immune microenvironment in tumor has been accepted as a key factor for determining the therapeutic outcome. Despite the diversity of immune infiltrates in lung adenocarcinoma, single-cell RNA sequencing has not yet been applied for a large-scale tumor and immune profiling.

    Method
    

    Samples were obtained from the primary tumor, lymph node or brain metastases, and pleural fluids of 44 patients with lung adenocarcinoma. Following lung tumor resection, normal lung tissues from a distal region as well as normal lymph nodes were collected for comparison. We dissociated the whole tissues into single cell suspension and then performed scRNA-seq using droplet-based 10x Genomics Chromiunm platform.

    Result
    

    After quality filtering, we cataloged a total of 208,506 cells into 9 distinct cell lineages annotated by expression of known marker genes. We identified epithelial cells including cancer cells, stromal cells (fibroblasts and endothelial cells), immune cells (T, NK, B, myeloid, and MAST cells) as common cell types, and oligodendrocytes uniquely from brain metastases. The most abundant immune cell populations at the lung tumor site were T lymphocytes and myeloid cells. Notably, primary tumor and lymph node metastases showed substantial differences in the immune cell composition. These differences reflected the original tissue microenvironment, grossly altered by tumor progression and invasion. Therefore, our lung adenocarcinoma atlas illustrates the dynamic cellular landscape during cancer progression which may reveal progression associated changes for each cellular component in unprecedented scale and manner.

    Conclusion
    

    These results provide specific tumor microenvironmental patterns in lung adenocarcinoma. Thus, single cell-level transcriptome profiles provide clues to expand therapeutic windows into the combination therapy with immune and anti-cancer reagents.

  • 30873

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    P1.04-24 - Circulating Suppressive Immune Cells Predict the Efficacy of Anti PD-1 Immunotherapy in Patients with Advanced Non-Small Cell Lung Cancer (ID 466)

    09:45 - 18:00  |  Author(s): Bo Mi Ku
    • Abstract

    Background
    

    The major suppressive immune cells in tumor sites are myeloid derived suppressor cell (MDSC), tumor associated macrophage (TAM), and regulatory T (Treg) cell, and the major roles of these suppressive immune cells include hindering T cell activities and supporting tumor progression and survival. In this study, we analyzed the pattern of various circulating suppressive immune cells in patients with non-small cell lung cancer (NSCLC) to see whether those suppressive immune cells hinder T cell activities leading to poor clinical outcomes.

    Method
    

    Baseline blood samples were collected from stage I to IV NSCLC patients (n=59), and baseline and one week after the therapy paired blood samples from stage IIIB to IV NSCLC patients (n=83) undergoing anti PD-1 immunotherapy either pembrolizumab or nivolumab. The efficacies of peripheral blood suppressive immune cells along with CD39⁺CD8⁺ T cells individually or collectively in anti-PD-1 immunotherapy were evaluated using flow cytometry and T cell suppressive assay.

    Result
    

    G-MDSCs, M-MDSCs, TAMs, Treg cells, and CD39⁺CD8⁺ T cells increased according to NSCLC stage, and MDSCs effectively suppressed T cell activities and induced T cell exhaustion ex vivo. Further, the analysis of 83 NSCLC patients treated with anti-PD-1 immunotherapy demonstrated that low G-MDSCs (P_PFS = 0.03, Pos = 0.04), M-MDSCs (P_PFS = 0.04, Pos = 0.005), TAMs (P_PFS = 0.007, Pos = 0.01), and CD39⁺CD8⁺ T cells (P_PFS = 0.57, Pos = 0.02) were associated with longer progression-free survival (PFS) and overall survival (OS) compared with high groups. When we performed combined analysis of three suppressive immune cells, G-MDSCs, M-MDSCs, and TAMs collectively, patients who had low frequency of all three suppressive immune cells showed more prominent difference of PFS (6.7 months vs 2 months; P = 0.006), OS (8.5 months vs 4.2 months; P = 0.004), and response rate (94.5% vs 50%) compared to patients with high levels of all three suppressive immune cells. We further sorted patients with all suppressive immune cells plus CD39⁺CD8⁺ T cells low and high. Again, PFS (6.1 months vs 0.8 months; P = 0.006), OS (11 months vs 2.4 months; P = 0.01), and response rate (85.7% vs 16.7%) of all suppressive immune cells low and CD39⁺ CD8⁺ T cells low group were significantly increased.

    Conclusion
    

    The analysis of 83 advanced NSCLC patients treated with anti-PD-1 immunotherapy demonstrated that G-MDSC, M-MDSC, TAM and CD39⁺CD8⁺ T cell frequencies in peripheral blood individually and collectively might be useful as potential predictive biomarkers.

• 31199

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  P2.09 - Pathology (ID 174)

  • Event: WCLC 2019
  • Type: Poster Viewing in the Exhibit Hall
  • Track: Pathology
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall

  • 31207

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    P2.09-07 - Multiple Immunohistochemistry of Non-Small Cell Lung Cancers Reveals Distinct Immune Context (ID 1232)

    10:15 - 18:15  |  Presenting Author(s): Bo Mi Ku
    • Abstract

    Background
    

    Immune checkpoint blockade improves survival in a subset of patients with non-small cell lung cancer (NSCLC). Though increased tumor infiltrating lymphocytes (TILs) correlate with better outcome in many human cancers, biomarkers that predict response to PD-1 pathway inhibitors remain largely unknown. Therefore, a comprehensive evaluation of the composition and distribution of TILs is necessary to demonstrate their roles.

    Method
    

    To determine the predictive significance of specific immune cells in the tumor microenvironment, we used multiples IHC. Multiplex IHC is a powerful investigative tool which provides objective quantitative data describing the tumor immune context in both immune subset number and location. To evaluate the immune context broadly we used the OPAL staining panel contains CD8, CD4, CD20, CD68, FOXP3, and panCK.

    Result
    

    Pathologic tumor specimens from 101 patients with recurred or metastatic NSCLC were analyzed. Tumors exhibited a high degree of heterogeneity in the immune infiltrate and there was no significant difference when immune infiltrates were compared by tumor histology. Furthermore, there were no significant immune cell differences in EGFR mutant tumors or tumors that did not harbor mutations in adenocarcinoma. We observed increased Tregs (CD4+/FOXP3+) in PD-L1-positive tumors as compared with PD-L1-negative tumors. Our results showed that the infiltration levels of most T-cell subpopulations within tumor did not significantly associated with survival. However, high infiltration of B cells significantly correlated with overall survival.

    Conclusion
    

    Increased infiltration of B cells into tumor regions is an independent predictor of better overall survival in NSCLC. These findings suggest that tumor-infiltrating B cells could act as a clinical factor in anti-PD-1 immunotherapy for NSCLC.

• 31515

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  P2.14 - Targeted Therapy (ID 183)

  • Event: WCLC 2019
  • Type: Poster Viewing in the Exhibit Hall
  • Track: Targeted Therapy
  • Presentations: 2
  • Moderators:
  • Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall

  • 31574

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    P2.14-54 - High Incidence of CNS Metastases in Advanced or Recurrent Non-Small Cell Lung Cancer Patients with RET Fusion (ID 1758)

    10:15 - 18:15  |  Author(s): Bo Mi Ku
    • Abstract

    Background
    

    Chromosomal rearrangements involving RET, with incidence of 1-2% in non-small-cell lung cancer, define a distinctive molecular subset. Here, we aim to determine the clinicopathological characteristics of patients with advanced NSCLC harboring the RET fusion gene.

    Method
    

    We identified 59 consecutive cases with RET rearrangements by using break-apart fluorescence in situ hybridization (n=14), next-generation sequencing (n=37), or both (n=8). Clinical data, including baseline characteristics, initial presentation, responses to chemotherapy and/or immunotherapy were retrospectively analyzed.

    Result
    

    The median age was 56 years, and 53% of patients were male. Approximately half of the patients (51%) were never-smokers. Adenocarcinoma was the predominant histologic subtype (90%), followed by pleomorphic (3%), neuroendocrine (3%), squamous cell (2%), and small cell carcinoma (2%). For the 19 patients with small primary lesions (<3cm), 32% (6/19) had N2 and 37% (7/19) had N3 disease. 17 patients (29%) had an intracranial lesion at the initial presentation or at the time of recurrence, and additional 11 patients (19%) developed brain metastasis during follow-up. Cerebrospinal fluid cytology exam confirmed leptomeningeal seeding in four patients (7%) with concomitant parenchymal metastasis. The median time to development of brain metastases was 19.0 months (range 3.8-51.8).

    Of 30 patients whose fusion partners were identified, kinesin family member 5B (KIF5B) was the most common, followed by coiled-coil domain containing 6 gene (CCDC6), nuclear receptor coactivator 4 (NCOA4), and myosin 5C (MYO5C) and lisH domain and HEAT repeat-containing protein KIAA1468 homolog (KIAA1468). Additionally, a novel fusion partner, phytanoyl-CoA 2-hydroxylase interacting protein like (PHYHIPL), was reported in one patient. Only two patients harbored concomitant EGFR mutation, and no ALK alterations were reported.

    The median overall survival was 35.3 months (95% confidence interval [CI]: 21.7-48.9). In 46 patients who were treated with pemetrexed-based chemotherapy, the overall response rate (ORR) and progression-free survival (PFS) time were 53.0% and 8.5 months (95% CI: 6.3-10.7), respectively. In 13 patients who were treated with immunotherapy, the ORR and PFS were 7.7% and 1.5 months (95% CI: 1.3-1.7), respectively, with no significant difference according to the level of PD-L1 expression.

    Conclusion
    

    Our study revealed the unique clinical characteristics and outcomes of advanced NSCLC patients harboring RET fusion gene. Considering the high incidence of CNS metastases, relatively poor response to immunotherapy, and a recent development of RET kinase inhibitors (such as cabozantinib and vandetanib), more efforts are warranted for identification of patients with RET fusion as a candidate for targeted therapies.

  • 31581

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    P2.14-61 - Acquired Resistance to Entrectinib Associated with Activation of RAS Signaling Pathway in ROS1-Rearranged Non-Small Cell Lung Cancer (ID 1219)

    10:15 - 18:15  |  Presenting Author(s): Bo Mi Ku
    • Abstract

    Background
    

    ROS1 is a receptor tyrosine kinase (RTK) that is not usually expressed at high levels in normal lung tissue. The wild-type function of ROS1 is unknown, and a natural ligand has not been identified. ROS1 gene rearrangements occur in ~1-2% of patients with NSCLC, and have also been identified in colorectal, gastric and ovarian cancers, glioblastoma and cholangiocarcinoma. ROS1 rearrangements with oncogenic potential have been found to constitutively activate ROS1 signaling, and although it remains unclear exactly how the ROS1 fusion proteins are activated, the PI3K/AKT, MAPK/ERK and JAK/STAT3 pathways are known to be involved. Thus, ROS1-rearranged NSCLCs are ‘addicted’ to ROS1 for cell growth and survival. Knocking down or pharmacologically inhibiting ROS1 has been reported to inhibit growth or induce apoptosis in ROS1-rearranged cell lines. Entrectinib is a pan-tyrosine-kinase inhibitor that targets oncogenic rearrangements in NTRK, ROS1 and ALK. The combined results of two clinical trials demonstrated the efficacy of entrectinib in ROS1-rearranged NSCLC. Because the development of drug resistance is inevitable, it would be helpful to determine the mechanisms of entrectinib resistance in a ROS1-rearranged tumor model so that future therapeutic strategies can be developed.

    Method
    

    To investigate the effects of entrectinib on ROS1-rearranged NSCLC, we used HCC78 cells harboring an SLC34A2-ROS1 fusion. Entrectinib-resistant HCC78 (HCC78ER) cells were newly established in our laboratory through the exposure of HCC78 cells to gradually increasing concentrations of entrectinib (starting at 100 nM and ending with 5 μM) over 6 months.

    Result
    

    Here, we characterized the molecular basis of resistance in entrectinib-resistant ROS1-rearranged HCC78 cells (HCC78ER cells). These cells were analyzed by next-generation sequencing and genetic profiling, which revealed the acquisition of KRAS G12C and the amplification of KRAS and FGF3. However, there were no secondary mutations in the ROS1 kinase domain. We also found that sustained ERK activation was involved in entrectinib resistance, and that combined treatment with selumetinib resensitized HCC78ER cells to entrectinib in cell viability and colony formation assays.

    Conclusion
    

    Our data suggest that activation of the RAS signaling pathway can cause entrectinib resistance in ROS1-rearranged NSCLC, and is unlikely to be overcome by sequential single agent ROS1-targeting strategies against such tumors. Instead, co-targeting ROS1 and MEK may be an effective strategy for overcoming entrectinib resistance in ROS1-rearranged NSCLC.