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T. Trojanowski
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P3.07 - Immunology and Immunotherapy (ID 723)
- Event: WCLC 2017
- Type: Poster Session with Presenters Present
- Track: Immunology and Immunotherapy
- Presentations: 1
- Moderators:
- Coordinates: 10/18/2017, 09:30 - 16:00, Exhibit Hall (Hall B + C)
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P3.07-013a - PD-L1 Expression, Using SP142 and 22C3 Antibody Clones, in NSCLC Patients with Known Status of EGFR and ALK Genes (ID 8323)
09:30 - 09:30 | Author(s): T. Trojanowski
- Abstract
Background:
Currently available immune-checkpoint inhibitor therapies in NSCLC patients have different, approved PD-L1 expression assays. These assays have similarities, but also some differences. In our study, we estimated usefulness of two immunohistochemical (IHC) tests in patients with different pathological diagnosis of lung cancer and known most common genetic abnormalities.
Method:
The study included 48 NSCLC patients (median age: 65 years old) with known status of EGFR and ALK genes. PD-L1 expression examination was carried out using two IHC assays with SP142 (Ventana) and 22C3 (Dako) antibodies. The analysis was performed in histological (resected tissue) and cytological (cellblocks from bronchoscopy biopsies) material in a form of formalin-fixed paraffin-embedded blocks, on corresponding analysis platforms.
Result:
The expression of PD-L1 of ≥5% and ≥50% on tumour cells (TCs) was significantly (p<0.05) higher in assay with 22C3 (66.7% and 45.8%) than with SP142 antibody (39.6% and 22.9%). The median percentage of PD-L1-expressing TCs was significantly (p<0.0001) higher in test with 22C3 than with SP142 antibody. PD-L1 expression on TCs was observed significantly higher in squamous cell carcinoma (SCC) patients than in PD-L1-positive non-SCC patients (p=0,0224). We have observed low percentage of PD-L1-positive cases among patients with common EGFR mutations and ALK rearrangement.
Conclusion:
Our results support that the highest PD-L1 expression on TCs occurs in SCC patients and in adenocarcinoma patients without common, druggable genetic abnormalities. The obtained results were clearly visible in assays with 22C3 antibody, whereas the SP142 antibody showed more diverse results in the same cases.
