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  P2.06 - Mesothelioma (Not CME Accredited Session) (ID 955)

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

  • 27051

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    P2.06-41 - Differentiating Sarcomatoid Mesothelioma from Pleomorphic Carcinoma and Chest Wall Sarcoma Using GATA-3/MUC4/BAP1 IHC (ID 12694)

    16:45 - 18:00  |  Author(s): Jan Lukas Robertus
    • Abstract
    • Slides

    Background
    

    Current immunohistochemistry (IHC) biomarkers, or so-called “mesothelial markers”, lack sensitivity and specificity in differentiating sarcomatoid mesothelioma from pleomorphic carcinoma of the lung, and poorly differentiated chest wall sarcoma. Hence it frequently poses a diagnostic challenge for pulmonary pathologists. In this pilot study we evaluated the diagnostic performance of two recently proposed IHC biomarkers, GATA-3 and MUC4, in conjunction with BAP1.

    a9ded1e5ce5d75814730bb4caaf49419 Method
    

    Sarcomatoid mesothelioma or sarcomatoid- predominant biphasic mesothelioma (10 cases), pleomorphic carcinoma of the lung (10 cases) and poorly differentiated primary or metastatic chest wall or pleural sarcoma (10 cases) were retrieved from our diagnostic archive. Resections or large biopsies were selected over small biopsies whenever possible. All the cases were diagnosed between 2009 and 2017 by a specialist pulmonary pathologist and discussed at the local multi-disciplinary team meeting in relation to final diagnosis. Whole slide GATA-3 (L50-823, pre-diluted), MUC4 (8G7, 1:50) and BAP1 (C-4, 1:50) immunohistochemistry was performed using Ventana Benchmark ULTRA system. Lymphocytes (GATA-3/BAP1) and bronchiolar epithelium (MUC4) were used as internal positive controls. Loss of GATA-3/BAP1 and MUC4 staining was defined as complete loss of nuclear or membrane & cytoplasmic signals, respectively. Any staining intensity above the external negative controls was accepted as positive. Extent of positive staining was grouped as <1%, 1-50% and >50%.

    4c3880bb027f159e801041b1021e88e8 Result
    

    GATA-3 was positive in 8/10 sarcomatoid mesothelioma, 6/10 chest wall/pleural sarcoma and 2/10 pleomorphic carcinoma of the lung. MUC4 positivity was observed exclusively in pleomorphic carcinoma of the lung (6/10), but only focally. BAP1 loss was infrequently observed in all three types of tumours.

    

    8eea62084ca7e541d918e823422bd82e Conclusion
    

    The combination of GATA-3 and MUC4 immunohistochemistry show promise as markers that would help in distinguishing these three tumours. The role of BAP1 is uncertain. These pilot results warrant an extended study that consists of a larger cohort to evaluate the utility of these biomarkers.

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