Author of

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  P1.14 - Thymoma/Other Thoracic Malignancies (Not CME Accredited Session) (ID 946)

  • Event: WCLC 2018
  • Type: Poster Viewing in the Exhibit Hall
  • Track:
  • Presentations: 1
  • Moderators:
  • Coordinates: 9/24/2018, 16:45 - 18:00, Exhibit Hall

  • 26650

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    P1.14-13 - PD-L1 Immuno-Expression Assay in Thymomas: A Study from India (ID 11244)

    16:45 - 18:00  |  Author(s): Saumya Shukla
    • Abstract
    • Slides

    Background
    

    Programmed death ligand 1 (PD-L1), an immune check point inhibitor, is known to be expressed in several malignancies and is being considered as a prognostic factor and a potential immunotherapeutic target. Recent development of anti-PD-1/L1 antibodies has demonstrated anticancer activity of these agents in various neoplasms. The aim of this study was to characterize PD-L1 expression in thymomas and to determine whether PD-L1 represents a therapeutic target in unresectable thymomas. A correlation with clinicopathological features and previously published studies in the literature was established.

    a9ded1e5ce5d75814730bb4caaf49419 Method
    

    Tissue microarrays were prepared from selected blocks of thymomas and immunohistochemistry (IHC) using SP263 clone of PD-L1 was performed. Cases were considered as PD-L1 positive or negative based on percentage of stained thymic epithelial cells; if these were <25 or >25 percent. Results were compared clinically and with previously published studies using Google and Pubmed search engines.

    4c3880bb027f159e801041b1021e88e8 Result
    

    Of 84 cases of thymoma, 69 (82.1%) revealed PD-L1 positivity in more than 25% cells. 94.23% of type B thymoma subtypes (B1/B2/B3) were PD-L1 positive (P<.001). There was no correlation of PD-L1 with age, gender, myasthenia gravis, the tumor size or stage of disease. So far, 9 studies of PD-L1 expression in thymic epithelial tumors are available in the literature; most of which showed PD-L1 expression in higher stage and B histotype however percentage positivity varied from 53.7% to over 90%.

    8eea62084ca7e541d918e823422bd82e Conclusion
    

    PD-L1 expression is frequent in type B (B1/B2/B3) thymomas. It can be easily evaluated by IHC even on small biopsies in unresectable cases. PD-L1 immunoassay will serve as a potential indicator for benefit from anti-PD-L1 antibody immunotherapy in thymomas thereby enabling improved clinical evaluation as well as prognostic stratification of patients.

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