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E. Maruyama



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    P1.02 - Poster Session 1 - Novel Cancer Genes and Pathways (ID 144)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Biology
    • Presentations: 1
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      P1.02-010 - Evaluation of the oncogenic ability of EML4-ALK to transform human bronchial epithelial cells (HBECs) (ID 1503)

      09:30 - 16:30  |  Author(s): E. Maruyama

      • Abstract

      Background
      Lung cancer is a highly lethal disease, and is believed to develop through a multistep carcinogenic process, which involves numerous genetic and epigenetic alterations. Among these alterations, mutations in “driver genes” such as KRAS and EGFR are found in non-small cell lung cancer (NSCLC) and they are demonstrated to contribute to a phenomenon, oncogene addiction. Recently, the EML4-ALK (echinoderm microtubule-associated protein–like 4 anaplastic lymphoma kinase) fusion gene has been discovered as a novel driver gene in a subset of NSCLC. We evaluated the oncogenic transformation ability of EML4-ALK by using an hTERT/CDK4-immortalized normal human bronchial epithelial cell (HBEC) model.

      Methods
      We used two HBEC lines, HBEC3 and HBEC4. Mutant KRAS[V12]-expressing HBEC was used as a positive control for oncogenic transformation. A lentiviral vector system was used to generate HBECs stably expressing EML4-ALK. EML4-ALK protein expression was confirmed by westernblotting, and downstream pathways were analyzed by westernblotting with phospho-specific antibodies. Malignant phenotypes of EML4-ALK-expressing HBECs were examined by WST-1 proliferation assay and liquid and soft agar colony formation assays.

      Results
      Westernblotting analysis showed that EML4-ALK was expressed in HBECs. Analysis of downstream pathways did not show significant differences between EML4-ALK-expressing and control HBECs. Introduction of EML4-ALK in HBECs increased the number of soft agar colonies but its effect was not as strong as KRAS[V12].Figure 1 A. Soft agar colony formation assay showing that EML4-ALK increased the number of colonies compared to control cells to a lesser extent than did KRAS[V12]. B. Cell proliferation assay (MTS-1) showing no significant difference between EML4-ALK-expressing and control HBECs.

      Conclusion
      EML4-ALK alone did not induce dramatic oncogenic changes in HBECs. To acquire more malignant phenotype, additional genomic alterations may be required and this is now under investigation.

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    P2.10 - Poster Session 2 - Chemotherapy (ID 207)

    • Event: WCLC 2013
    • Type: Poster Session
    • Track: Medical Oncology
    • Presentations: 1
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      P2.10-026 - Final results of EGFR mutation reanalysis and KRAS mutation screening by Scorpion ARMS method: Phase II Study of Erlotinib for EGFR wild type Non-small cell Lung Cancer Patients. Central Japan Lung Study Group (CJLSG) 0903 trial. (ID 1529)

      09:30 - 16:30  |  Author(s): E. Maruyama

      • Abstract

      Background
      Erlotinib might benefit non-small cell lung cancer (NSCLC) patients with EGFR wild-type (WT) genotype based on the subgroup analysis of the BR21 trial and SATURN trial. However, the sensitivity of methods for detection of EGFR mutation can influence the evaluation of erlotinib efficacy. We conducted CJLSG0903 trial, a phase II study of erlotinib for previously treated EGFR WT NSCLC patients screened by peptide nucleic acid-locked nucleic acid (PNA-LNA) PCR clamp method. The efficacy and safety results of CJLSG0903 were previously reported at the ESMO meeting 2012. Here we present the final results of EGFR mutation reanalysis and KRAS mutation screening by S-ARMS method.

      Methods
      Stage IIIB or IV NSCLC patients were eligible. EGFR mutation status was screened by PNA-LNA PCR clamp method, which is known to be a highly sensitive. Primary endpoint was objective response rate (ORR). Oral erlotinib 150 mg was given daily until progression or unacceptable toxicity.

      Results
      From February 2010 and April 2012, 53 evaluable patients were enrolled. ORR was 11.3% (95% confidence interval: 4.3–23.0%). We performed preplanned reanalysis of EGFR mutation status and KRAS mutation by Scorpion ARMS (S-ARMS) methods if remaining samples from participants were available. Samples from 26 patients (49%) were available for EGFR mutation reanalysis. Only one patient who achieved partial response (PR) was EGFR mutation positive (exon 19 deletion). In 25 patients, EGFR WT genotype was reconfirmed by S-ARMS method. Two of them achieved PR. ORR was 8.0 % in patient with EGFR WT genotype confirmed by both PNA-LNA PCR clamp and S-ARMS methods. Samples from 42 patients (79%) were available for KRAS mutation screening. KRAS mutations were detected in 4 of 42 patients, and progressive disease (PD) was observed in all of KRAS mutation positive patients.

      Conclusion
      Erlotinib still shows activity in patients with EGFR WT genotype confirmed by two different highly sensitive methods. Activating KRAS mutation might be negative predictive factor for erlotinib efficacy in patients with EGFR WT genotype. (UMIN Clinical Trials Registry: UMIN000002692)