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I. Kern
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P2.09 - Mesothelioma (ID 710)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Mesothelioma
- Presentations: 1
- Moderators:
- Coordinates: 10/17/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P2.09-004 - PD-L1 Protein Expression Is Negative Prognostic Factor in Malignant Pleural Mesothelioma in Central Europe (ID 9558)
09:30 - 09:30 | Author(s): I. Kern
- Abstract
Background:
Early data on immune-checkpoint blockade with PD-1 inhibitors show promising response rates and survival benefit mainly in PD-L1 positive malignant pleural mesothelioma (MPM) patients. Reported rate of PD-L1 positivity of MPM is between 20-40%. However, the role of PD-L1 protein expression positivity in prediction of a response to PD-1/PD-L1 inhibitors remains controversial. We assessed the prognostic value of PD-L1 expression in patients with MPM in central Europe.
Method:
We evaluated protein expression of PD-L1 in formalin-fixed paraffin-embedded surgical specimens of 176 MPM patients from Austria, Croatia, Hungary and Slovenia. PD-L1 antibody clone E1L3N (Cell Signaling) was used. Cut-off point of >10% of PD-L1-positive tumor cells at any staining intensity was correlated with clinicopathologic characteristics (age, gender, IMIG clinical stage, histology (epithelioid vs non-epithelioid) and survival).
Result:
There were altogether 49 females and 127 males, median age 63 years. PD-L1 protein expression of >10% was observed in higher proportion in a patient with higher IMIG stage (III+IV vs. I+II), as well as in patients with non-epithelioid histology, later being also statistically significant (p=0.0026). Median survival of patients with high PD-L1 expression (>10%) in tumor cells was significantly shorter in comparison with patients demonstrating lower PD-L1 expression (26 vs. 67 weeks respectively, p<0.001). PD-L1 expression (>10%) proved to be an independent prognostic factor in a multivariate cox regression analysis (hazard ratio [HR] 2.902; 95% confidence interval [CI] 1.425 to 5.937; p = 0.003).
Conclusion:
High expression of PD-L1 on tumor cells (>10%) is negative independent prognostic factor in malignant pleural mesothelioma regardless of histology.