Author of

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  P37 - Pathology - Biomarker Testing (ID 107)

  • Event: WCLC 2020
  • Type: Posters
  • Track: Pathology, Molecular Pathology and Diagnostic Biomarkers
  • Presentations: 1
  • Moderators:
  • Coordinates: 1/28/2021, 00:00 - 00:00, ePoster Hall

  • 34814

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    P37.26 - Comprehensive Comparison of 22C3 and SP263 PD-L1 Expression using Routine Clinical and Conditioned Archives of Non-Small-Cell Lung Cancer (ID 2533)

    00:00 - 00:00  |  Presenting Author(s): Tae Jung Kim
    • Abstract
    • Slides

    Introduction
    

    Harmonization studies for PD-L1 revealed high correlation of 22C3 and SP263 antibodies in non-small cell lung cancer (NSCLC). However, characteristics of those antibodies in various clinical and analytical setting has yet to be validated.

    Methods
    

    The results of simultaneously performed PD-L1 22C3 and SP263 assays on 431 routine clinical NSCLC samples were reviewed and both assays were performed on 314 archives of surgically resected NSCLCs and assessed the PD-L1 expression according to FFPE block age, and the storage duration and the temperature of FFPE sections.

    Results
    

    In routine clinical samples, 22C3 showed highest concordance rate with 94.5% of SP263 tumor proportion score (TPS) ≥50% and 98.9% 78.8% of SP263 TPS 1-49%, while SP263 showed concordance rate with 79.6% of 22C3 TPS ≥50% and 82.4% of 22C3 TPS 1-49%. In archives, both 22C3 and SP263 high TPS (versus TPS <1%) were significantly associated with more recent block (<3 years versus ≥3 years) (p = 0007 and p = 0.009, respectively). When FFPE sections were stored at room temperature, only 22C3 TPS was more decreased in longer stored sections. However, the expression was not affected by the section storage duration in both assays when stored at 4C. For 22C3 TPS 1-49% and ≥50%, there was a significantly higher probability of preserved 22C3 expression in resent section in room temperature (OR = 1.73, p = 0.006 and OR = 1.98, p = 0.002, respectively) but SP263 showed preserved expression in longer section duration in room temperature.

    Conclusion
    

    Our results showed the high correlation between PD-L1 22C3 and SP263 in routine clinical samples but FFPE block older than 3 years and sections stored at room temperature more than 1 week may lead to underestimation of PD-L1 status especially with 22C3 assay

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