| Autor: |
de Ruiter EJ; Department of Pathology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. e.j.deruiter@umcutrecht.nl., Mulder FJ; Department of Pathology, Maastricht University Medical Center, Maastricht, The Netherlands., Koomen BM; Department of Pathology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands., Speel EJ; Department of Pathology, Maastricht University Medical Center, Maastricht, The Netherlands., van den Hout MFCM; Department of Pathology, Maastricht University Medical Center, Maastricht, The Netherlands., de Roest RH; Department of Otolaryngology/Head and Neck Surgery, Amsterdam UMC, Cancer Center, Amsterdam, The Netherlands., Bloemena E; Department of Pathology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.; Department of Maxillofacial Surgery/Oral Pathology, Amsterdam UMC and Academic Centre for Dentistry Amsterdam (ACTA), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands., Devriese LA; Department of Medical Oncology, University Medical Center Utrecht, Utrecht, The Netherlands., Willems SM; Department of Pathology, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX, Utrecht, The Netherlands. |
| Abstrakt: |
Expression of programmed cell death-ligand 1 (PD-L1) is being used as predictive biomarker for immunotherapy in head and neck squamous cell carcinoma (HNSCC). Several antibodies are available for PD-L1 testing and multiple staining and scoring methods are used. This study aimed to compare the performance of two PD-L1 standardized assays (SP263 and 22C3 pharmDx) and one laboratory-developed test (LDT) (22C3) in HNSCC using the tumor proportion score (TPS) and the combined positive score (CPS). Pretreatment biopsies from 147 HNSCC patients were collected in a tissue-microarray (TMA). Serial sections of the TMA were immunohistochemically stained for PD-L1 expression using 22C3 pharmDx on the Dako Link 48 platform, SP263 on the Ventana Benchmark Ultra platform, and 22C3 as an LDT on the Ventana Benchmark Ultra. Stained slides were assessed for TPS and CPS. Cutoffs of ≥1% and ≥50% for TPS and ≥1 and ≥20 for CPS were used. Concordance between the different staining assays was moderate to poor for TPS (intraclass correlation coefficient (ICC) 0.46) as well as for CPS (ICC 0.34). When stratifying patients by clinically relevant cutoffs, considerable differences between the assays were observed: concordance was poor for both TPS and CPS. Generally, SP263 stained a higher percentage of cells than the other assays, especially when using the CPS. Moderate concordance was shown between three different PD-L1 immunohistochemical assays and considerable differences in PD-L1 positivity were observed when using clinically relevant cutoffs. This should be taken into account when using PD-L1 expression to guide clinical practice. |
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