Author of

• 12441

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  P3.06 - Poster Session 3 - Prognostic and Predictive Biomarkers (ID 178)

  • Event: WCLC 2013
  • Type: Poster Session
  • Track: Biology
  • Presentations: 1
  • Moderators:
  • Coordinates: 10/30/2013, 09:30 - 16:30, Exhibit Hall, Ground Level

  • 12472

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    P3.06-032 - Evaluation of Anaplastic lymphoma kinase (ALK) rearrangements using ALK/EML4 TriCheck Fluorescence In Situ Hybridisation (FISH) in Non-Small Cell Lung Cancers (NSCLC) and its utility for equivocal cases. (ID 2487)

    09:30 - 09:30  |  Author(s): T. Lum
    • Abstract

    Background
    Accurate assessment of ALK gene rearrangement in NSCLCs is critical to identify patients likely to respond to crizotinib. Currently, the gold standard for identifying ALK gene rearrangements is FISH and the Abbott Molecular ALK break apart probe is commonly used. We evaluated a new ALK/EML4 TriCheck FISH Probe for the detection of ALK rearrangements and confirmation of EML4 as the inversion partner. In addition, we evaluated its use as an ancillary FISH probe for use in cases with subtle, equivocal or atypical ALK FISH patterns.

    Methods
    ALK FISH was prospectively performed on 29 routine diagnostic cases using the ALK/EML4 TriCheck Probe (ZytoVision) and the Vysis ALK Break Apart FISH Probe (Abbott Molecular). ALK immunohistochemistry (IHC) was performed using the 5A4 clone antibody (Novocastra) and D5F3 clone antibody (Cell Signaling Technology).

    Results
    Both probes were concordant in all cases, except for one case which showed an atypical signal pattern using the Abbott Molecular ALK probe. This case was technically negative using standard scoring criteria for the Abbott probe, despite positive ALK IHC, but was confirmed as positive using the ZytoVision TriCheck probe. Two additional cases which were equivocal (10-16% ALK rearrangement), were confirmed to be positive for ALK rearrangement using the ALK/EML4 TriCheck probe. Of the 10 ALK rearranged cases, 4 showed evidence of EML4 translocation.

    Conclusion
    The ALK/EML4 TriCheck FISH Probe is useful for the detection of ALK gene rearrangements, including those involving EML4 as the translocation partner, especially for borderline cases or cases displaying atypical signal patterns, where an additional unique ALK FISH probe can provide further confirmation of rearrangement.