Author of

• 17398

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  P2.01 - Poster Session with Presenters Present (ID 461)

  • Event: WCLC 2016
  • Type: Poster Presenters Present
  • Track: Biology/Pathology
  • Presentations: 1
  • Moderators:
  • Coordinates: 12/06/2016, 14:30 - 15:45, Hall B (Poster Area)

  • 17452

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    P2.01-054 - Lung Cancer PD-L1 mRNA Expression Profile and Clinical Outcomes - An Analysis From The Cancer Genome Atlas and Cancer Cell Line Encyclopedia (ID 5048)

    14:30 - 14:30  |  Author(s): J. Roszik
    • Abstract

    Background:
    Programmed death ligand 1 (PD-L1) has become one of the most studied biomarkers in early, and advanced non-small cell lung cancers (NSCLC). Conflicting results have been reported in the literature on the value of PD-L1 in predicting survival in surgically resected lung cancers. Our aim was to evaluate mRNA PD-L1 expression and survival based on the data available from the Cancer Genome Atlas (TCGA), and Cancer Cell Line Encyclopedia (CCLE).
    
    Methods:
    To determine the expression profile and clinical correlations of PD-L1 in lung cancers we used publicly available lung adenocarcinoma and squamous cell carcinoma (SCC) data from TCGA, and small cell and NSCLC line data from the CCLE. We performed Kaplan-Meier and correlation analyses to show how PD-L1 expression correlates with overall survival and other clinical variables. Lung cancer and normal tissue expression comparisons were also performed using normal tissue expressions from the Genotype-Tissue Expression (GTEx) project.
    
    Results:
    Results: PD-L1 mRNA expression from RNA sequencing was available for 517 lung adenocarcinoma and 501 lung SCC samples in the TCGA. The CCLE database contained PD-L1 expression for 12 small cell and 75 NSCLC cell lines. Lung cancers demonstrated a higher PD-L1 expression than most other cancers and normal tissues, and we found that PD-L1 expression was significantly higher in SCC than in adenocarcinoma (p<0.001). Furthermore, PD-L1 showed a significantly higher expression level in pathologic stage II SCC compared to stages I, III, and IV (p<0.05, p<0.05, p<0.001, respectively). Interestingly, stage IV was associated with a lower PD-L1 expression compared to stages I, II, and III (p<0.001). We did not identify similar expression associations with pathologic stage in adenocarcinoma. However, we found that current and also reformed smokers for less than 15 years had a higher PD-L1 expression in adenocarcinoma (p<0.05), but not in SCC. PD-L1 expression was not significantly associated with a survival difference in any stage or histology subgroups. Using the CCLE data we found that NSCLC cell lines show various expression of PD-L1 that is significantly higher compared to lung small cell carcinoma (p<0.001).
    
    Conclusion:
    The value of PD-L1 expression based on mRNA sequencing in predicting survival in anti PD-1 naïve patients appears to be limited. However, the levels of PD-L1 expression in various disease stages and subgroups of lung cancer patients provide rational for neoadjuvant or window-of-opportunity immunotherapy trials, which would enable us to sort out the mechanisms and to identify patients best suited for immunotherapy.