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  P2.09 - Pathology (Not CME Accredited Session) (ID 958)

  • Event: WCLC 2018
  • Type: Poster Viewing in the Exhibit Hall
  • Track:
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/25/2018, 16:45 - 18:00, Exhibit Hall

  • 27061

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    P2.09-09 - Precision and Repeatability of VENTANA DLL3 (SP347) Assay Immunohistochemistry Assay in Fine Needle Aspirations of Small Cell Lung Cancer (ID 12809)

    16:45 - 18:00  |  Author(s): Bita Damadzadeh
    • Abstract
    • Slides

    Background
    

    Fine needle aspirations (FNA) are a common type of sample that is obtained for diagnostic purposes in small cell lung cancer (SCLC) patients due to its relatively less invasive nature. Several delta-like protein 3 (DLL3) therapies that target DLL3 in SCLC are under development. We recently developed an immunohistochemistry assay utilizing a rabbit monoclonal antibody that can be used to identify patients that may potentially respond to DLL3 targeted therapies. Due to the high prevalence of FNA samples in SCLC, the robustness of the VENTANA DLL3 (SP347) Assay (DLL3 (SP347)) in FNAs is examined.

    a9ded1e5ce5d75814730bb4caaf49419 Method
    

    Formalin-fixed, paraffin-embedded (FFPE) FNA samples of SCLC were used in a series of studies addressing precision of performance of DLL3 (SP347). FNA SCLC samples were stained with the VENTANA DLL3 (SP347) Assay and assessed by a pathologist for percent tumor cell staining (%TC), at any stain intensity at ≤4X magnification. The samples were placed into quartile bins (0-24, 25-49, 50-74 and 75-100 %TC) and evaluated for intra-day repeatability and inter-day precision. For each case, the modal staining result based on %TC bin was determined and the result from each test sample was compared to its respective case-level modal staining result and deemed concordant or discordant. Results were aggregated across cases and the overall percent agreement (OPA) was calculated for each study.

    4c3880bb027f159e801041b1021e88e8 Result
    

    Both studies (Table 1) showed >90% OPA for DLL3 concordance to the %TC bins.

    Table 1: Precision and Repeatability of FNA SCLC Samples

    Study	# of Cases	# DLL3 Observations	OPA
    Intra-day	21	63	100%
    Inter-day	21	124	98.4

    8eea62084ca7e541d918e823422bd82e Conclusion
    

    The presented data shows that VENTANA DLL3 (SP347) Assay can precisely evaluate DLL3 expression in FNA SCLC samples.

    6f8b794f3246b0c1e1780bb4d4d5dc53

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