CD274/PD-L1 gene amplification and PD-L1 protein expression are common events in squamous cell carcinoma of the oral cavity.

DOI
Publisher DOI
PubMed ID
26918453
Abstract
Immunomodulatory therapies, targeting the immune checkpoint receptor-ligand complex PD-1/PD-L1 have shown promising results in early phase clinical trials in solid malignancies, including carcinomas of the head and neck. In this context, PD-L1 protein expression has been proposed as a potentially valuable predictive marker. In the present study, expression of PD-L1 and PD-1 was evaluated by immunohistochemistry in 80 patients with predominantly HPV-negative oral squamous cell carcinomas and associated nodal metastasis. In addition, CD274/PD-L1 gene copy number status was assessed by fluorescence in situ hybridization analysis. PD-L1 expression was detected in 36/80 (45%) cases and concordance of PD-L1 expression in primary tumor and corresponding nodal metastasis was present in only 20/28 (72%) cases. PD-1 expression was found in tumor-infiltrating lymphocytes (TILs) but not in tumor cells. CD274/PD-L1 gene amplification was detected in 19% of cases, with high level PD-L1 amplification present in 12/80 (15%), and low level amplification in 3/80 (4%). Interestingly, CD274/PD-L1 gene amplification was associated with positive PD-L1 immunostaining in only 73% of cases. PD-L1 copy number status was concordant in primary tumor and associated metastases. Clinically, PD-L1 tumor immunopositivity was associated with a higher risk for nodal metastasis at diagnosis, overall tumor related death und recurrence. Based on our findings we propose to include PD-L1 copy number status in addition to protein status in screening programs for future clinical trials with immunotherapeutic strategies targeting the PD-1/PD-L1 axis.
Date Issued
2016-03-15
Publication Type
Article
Subject(s)
Subjects
PD-1
•
PD-L1
•
Pathology Section
•
fluorescence in situ hybridization
•
gene amplification
•
oral squamous cell carcinoma
Language(s)
en
Author(s)
Straub, Melanie
Drecoll, Enken
Pfarr, Nicole
Weichert, Wilko
Hapfelmeier, Alexander
Götz, Carolin
Wolff, Klaus-Dietrich
Kolk, Andreas
Specht, Katja
Additional Credits
Journal
OncoTarget
Publisher
Impact Journals LLC
ISSN
1949-2553
Access(Rights)
open.access
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