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Bibhusal Thapa

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    OA08 - Mesothelioma: Immunotherapy and microRNA for Diagnosis and Treatment (ID 907)

    • Event: WCLC 2018
    • Type: Oral Abstract Session
    • Track: Mesothelioma
    • Presentations: 1
    • Moderators:
    • Coordinates: 9/24/2018, 15:15 - 16:45, Room 201 BD
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      OA08.05 - Quantifying Tumour Infiltrating Lymphocytes (TILs) in Malignant Pleural Mesothelioma (MPM) -Defining the Hot, the Warm and the Cold Tumours. (ID 13326)

      16:00 - 16:10  |  Author(s): Bibhusal Thapa

      • Abstract
      • Presentation
      • Slides


      Immunological infiltrates into tumor tissues have been associated with improved prognosis in many cancers including breast, colorectal, cervical, melanoma and lung. While most studies evaluating TILs have been based on evaluation of individual types of T lymphocytes, more recently, a morphological assessment of the TILs based on a simple hematoxylin & eosin (H&E) slide examination has been shown to be an independent positive prognostic factor in HER2 positive early stage breast cancer and lung cancer. We used similar methods to explore the immune microenvironment in a large mesothelioma cohort.

      a9ded1e5ce5d75814730bb4caaf49419 Method

      Using full face sections of MPM tumour samples, we assessed lymphocytes infiltrating tumour stroma.TILs score was calculated as a % of stromal area assessed to be covered by TILs by an experienced pathologist. Tissue microarrays (TMA) were constructed and stained with PD-L2, LAG3 and TIM3 antibodies. These data were combined with PD-L1 expression, CD4+ and CD8+ infiltration in the same cohort reported previously. We explored the clinical and pathological correlates of the level of TILs.

      4c3880bb027f159e801041b1021e88e8 Result

      Amongst 329 patients evaluated, 308 samples were evaluable for TILs characterisation. The scores ranged from 0-90 (median 30). Stratified using tertiles, 142 patients had low TILs, 68 had medium and 98 had high TILs. High TILs were seen in patients who were PD-L1 (Chi square test p = 0.002) and PD-L2 positive (Chi square test p <0.0001) and of non-epithelioid histological subtype (Fischer’s exact test p = 0.01). On univariate analysis, PD-L2 positivity (HR = 3.2; CI = 2.2-4.6; Log rank P < 0.0001), high TILs (HR = 2.03; CI = 1.5-2.6; Log rank P < 0.0001), and high TIM3+ lymphocytes (HR = 1.3; CI = 1.0-1.7; Log rank P < 0.04) were found to be related to poorer overall survival (OS). On multivariate analysis, higher TILS was found to remain significantly associated with poorer OS along with non-epithelioid histology and poor physiological status.

      8eea62084ca7e541d918e823422bd82e Conclusion

      High TILs correlated with non-epithelioid histology and greater expression of PD-L1 and PD-L2. In contrast to other tumor types, a high TIL infiltrate was negatively prognostic.


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