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K. Takahashi



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    P1.02 - Poster Session with Presenters Present (ID 454)

    • Event: WCLC 2016
    • Type: Poster Presenters Present
    • Track: Biology/Pathology
    • Presentations: 1
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      P1.02-068 - The Impact of TP53 Overexpression on EMT and the Prognosis in Lung Adenocarcinoma Harboring Driver Mutations (ID 4489)

      14:30 - 14:30  |  Author(s): K. Takahashi

      • Abstract
      • Slides

      Background:
      Epithelial-mesenchymal transition (EMT) and p53 mutations are known to be pivotal for driving metastasis and recurrence in lung cancer, but the nature of these factors is not completely understood. Some papers have previously described the relationship between EMT and TP53 in other carcinomas, however there have been few reports about the impact of TP53 on EMT and prognosis in lung adenocarcinoma harboring driver mutations such as EGFR or K-ras.

      Methods:
      The aim of the present study is to clarify the impact of TP53 overexpression in lung adenocarcinoma with driver mutations. A total of 282 lung adenocarcinoma specimens were collected from patients who had undergone surgery in our institute from January 2001 to December 2007. Both EMT markers (E-cadherin, vimentin) and TP53 were analyzed through immunostaining of tumor specimens. The association between EMT and TP53 as well as the patients’ clinical information was integrated and statistically analyzed. EGFR and K-ras mutation were determined by single stranded conformational polymorphism and direct sequencing. Correlations were compared using Pearson's chi-square test and overall survival were compared using the log-rank test.

      Results:
      Both mesenchymal type (E-cadherin negative, vimentin positive) and TP53 overexpression were significantly correlated with poor prognosis (P=0.0001, P=0.0019). A positive correlation was found between EMT activation level and TP53 overexpression (P=0.017). TP53 overexpression was significantly correlated with poor prognosis in the subgroup of lung adenocarcinoma with driver mutation (EGFR or K-ras) (P=0.011, P=0.026), whereas there was no significant correlation between TP53 overexpression and the prognosis in adenocarcinoma without driver mutations (P=0.359).

      Conclusion:
      TP53 overexpression is supposed to be the key factor that affects EMT and the prognosis, and also might be an additional therapeutic target for lung adenocarcinoma with driver mutations.

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    P2.04 - Poster Session with Presenters Present (ID 466)

    • Event: WCLC 2016
    • Type: Poster Presenters Present
    • Track: Mesothelioma/Thymic Malignancies/Esophageal Cancer/Other Thoracic Malignancies
    • Presentations: 1
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      P2.04-018 - Comprehensive Copy Number Alteration and Gene Expression Analysis of Surgically Resected Thymic Carcinoma (ID 4725)

      14:30 - 14:30  |  Author(s): K. Takahashi

      • Abstract

      Background:
      Thymic carcinoma is rare and comparatively poor prognostic. Due to its rarity, our knowledge of treatments and prognostic biomarkers available for these tumors is limited. Previous reports revealed low genetic mutation frequency of the tumors, and the inverse correlation between the frequency of genetic mutation and copy number alteration (CNA). Based on these reports, we hypothesized tumorigenesis of thymic carcinomas is mostly caused by copy number and transcriptional alterations. To substantiate the hypothesis, we extracted and analyzed CNA and gene expression data from surgical samples to elucidate driver genes, druggable targets and prognostic factors.

      Methods:
      Between January 2009 and March 2016, patients underwent surgery for thymic epithelial tumor in our institution were reviewed. RNA and DNA of the tumors were extracted from FFPE operative samples, gene expression data were obtained by GeneChip Human Transcriptome Array 2.0 (affymetrix), and CNA were detected by OncoScan (affymetrix). These results were analyzed using Transcriptome analysis console (affymetrix) and Nexus expression for OncoScan (BioDiscovery). Upregulated genes in copy number gained region and down regulated genes in copy number lost region were selected as a candidate of tumorigenesis of thymic carcinoma.

      Results:
      We had 10 thymic squamous cell carcinoma samples. As a comparison, we use three samples of type A thymoma. CNA data from thymic squamous cell carcinoma showed similar characteristics, chromosome 1q gain, 6p and q loss, and 16q loss, corresponding with previous reports. Gene expression analysis of thymic carcinoma in comparison with type A thymoma revealed down regulation of the genes, BRD2, HSP90AB1, FOXO3, and MARCKS in chromosome 6, and MTSS1L in chromosome 16q. Figure 1



      Conclusion:
      We reported the results of genome wide gene expression and CNA analysis. We extracted some candidate genes, but farther validations are needed.