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Jordi Bertrán-Alamillo



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    P2.01 - Advanced NSCLC (ID 159)

    • Event: WCLC 2019
    • Type: Poster Viewing in the Exhibit Hall
    • Track: Advanced NSCLC
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/09/2019, 10:15 - 18:15, Exhibit Hall
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      P2.01-56 - Copy Number Gains (CNGs) of Clinically Relevant Genes in Advanced NSCLC Patients (ID 2519)

      10:15 - 18:15  |  Author(s): Jordi Bertrán-Alamillo

      • Abstract

      Background

      Somatic copy number variations (CNV; i.e. amplifications and deletions) have been implicated in the origin and development of multiple cancers and some of these aberrations are designated targets for therapies, such as amplified ERBB2 in breast cancer. In the case of NSCLC patients, MET alterations are receiving increasing attention as targets in precision medicine, and several clinical trials of anti-MET agents are ongoing. Routine testing for these potential targets on formalin-fixed paraffin embedded (FFPE) samples is mainly carried out by in-situ hybridization (FISH) approaches covering only a single gene of interest. Although this methodology is still the gold standard of CNV detection, it presents several drawbacks. Here we aimed to determine the potential of next generation sequencing (NGS) to simultaneously determine CNGs across many in FFPE samples

      Method

      FFPE biopsies from 140 stage IIIb-IV NSCLC patients (p) of our institution were prospective tested. Of them, 110 corresponded to samples at diagnostic and 30 after progression to targeted therapies. DNA was purified submitted to NGS using the 16-gene QIAact Lung Panel (Genereader®, Qiagen). Coverages for the genes analyzed were normalized using the total coverage of the panel. Cut-off values for CNVs were established as the average normalized coverage for each gene plus two times the standard deviation. Representative samples were analyzed by FISH

      Result

      Validation analyses in 8 cell lines showed 100% concordance between FISH and NGS for detection of EGFR, MET and ERBB2 amplifications. Among the 140 NSCLC p, MET was the gene showing a higher frequency of CNGs, followed by PIK3CA, NRAS, EGFR and KRAS (Table 1). In contrast, only one p was found to harbor a ROS1 CNG. Among the 17 samples with MET CNG (12%), 6 corresponded to p progressing to targeted therapies. In addition, 8 of the 17 samples with MET CNGs were submitted to FISH, 6 of them were positive and the remaining 2 samples had copy numbers higher than 3.5 by this technique. In the case of EGFR, CNGs were associated with sensitizing mutations, with 5 samples showing both alterations concomitantly. In contrast, PIK3CA, NRAS, ALK, BRAF, HER2, PDGFRA, KIT and MET CNGs were not associated with mutations (Table 1).

      n CNG

      %

      n MUTANT

      MET

      17

      12.1

      0

      PIK3CA

      12

      8.6

      0

      NRAS

      10

      7.1

      0

      EGFR

      10

      7.1

      5

      KRAS

      10

      7.1

      2

      ALK

      8

      5.7

      0

      BRAF

      8

      5.7

      0

      ERBB2

      8

      5.7

      0

      PDGFRA

      6

      4.3

      0

      KIT

      6

      4.3

      0

      ROS1

      1

      0.7

      0

      Conclusion

      CNGs in clinically relevant genes are present in a significant percentage of advanced NSCLC patients and, except in the case of EGFR, are not associated with driver mutations. Further research is warranted to determine the clinical implications of this finding.