Author of

• 18975

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  P3.01 - Advanced NSCLC (ID 621)

  • Event: WCLC 2017
  • Type: Poster Session with Presenters Present
  • Track: Advanced NSCLC
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)

  • 23926

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    P3.01-067 - TP53 Mutations Could Involved in EGFR-TKI Primary Resistance in Advanced Non-Small Cell Lung Cancer (ID 10437)

    09:30 - 09:30  |  Author(s): Y. Shao
    • Abstract

    Background:
    Activating mutations in the epidermal growth factor receptor (EGFR) are strongly predictive of EGFR-tyrosine kinase inhibitor (TKI) activity in non-small cell lung cancer (NSCLC). However, primary resistance to EGFR-TKIs occurs in approximately 20-30% of NSCLC patients with EGFR mutations, acquired resistance is inevitable. The aim of study is to discover unknown resistant mechanisms and contribute to more precisely administrate advanced and metastatic NSCLC with EGFR mutations.
    
    Method:
    60 NSCLC patients with EGFR sensitive mutation were enrolled this study. All of patients received EGFR-TKI treatment. 21 of patients were primary resistance and 39 acquired resistance according to Jackman standard. Tumor tissues of all of patients were collected before EGFR-TKIs treatment, and rebiopsy tissues were gained after acquired resistance in 39 NSCLC patients. Whole exome sequencing were performed in Illumina HiSeq2000 platform. The captured sequencing data was further processed to identify somatic mutations, including single nucleotide variants (SNVs), short insertions/deletions (indels) and copy number variations (CNVs).
    
    Result:
    In primary resistance patients, 13 patients occurred rapid progress (PFS ≤60 days) were put into group 1, and other 8 patients with PFS within 90-180 days were into group 2; in acquired resistance patients, 9 patients were observed long-term clinical benefit (PFS≥540 days) were into group 3; remaining 30 patients with PFS between 180 to 540 days were into group 4. Median PFS were 29, 95, 761 and 311 days from group 1 to 4, respectively. More signaling pathways were activated in group 1, relative to other groups, including bypass activation, downstream signal activation, apoptotic pathways disturbance and EMT activation. Meanwhile, the activation of more signaling pathways were found in samples after acquired resistance compared with paired baseline samples. In all of baseline samples, 60.0% patients harbored TP53 mutations, and these mutations distributed in exon 2,4,5,6,7,8 and 11, respectively. Interestingly, TP53 mutations of 23% patients were in exon 6 in group 1, mutations in exon 5 occurred in 33.3% patients with long-term clinical benefit (group 3). Patients with exon 6 mutation had more shorter PFS than those with exon 5 mutation (105 days vs 284 days).
    
    Conclusion:
    For patients resistant to EGFR-TKI, more signal pathways were activation, and the heterogeneity of tumor cloning were complicated. TP53 mutations in different exons may have distinct effect on response to EGFR-TKI of patients with EGFR sensitive mutation.