Is there evidence for the presence and relevance of the PD-1/PD-L1 pathway in oral squamous cell carcinoma? Hints from an immunohistochemical study

Publication date: Available online 15 November 2016
Source:Journal of Oral and Maxillofacial Surgery
Author(s): Matthias Troeltzsch, Timothy Woodlock, Alix Pianka, Sven Otto, Markus Troeltzsch, Michael Ehrenfeld, Thomas Knösel
PurposeTo examine OSCC specimens for programmed death - ligand - 1 (PD - L1) expression and presence of programmed death - 1 (PD - 1) positive tumor infiltrating lymphocytes (TIL) and to reveal possible clinicopathological implications. It was hypothesized that in case of PD - L1 expression and PD - 1 positive TIL presence of OSCC this would be without clinical relevance.MethodsThe investigators implemented a retrospective cohort study design. The study cohort was chosen in compliance with predefined inclusion criteria. Demographic, clinical and histopathological data were gathered. Tissue microarrays (TMA) were obtained from paraffin embedded OSCC specimens and analyzed immunohistochemically for PD - L1 expression and PD - 1 positive TIL infiltration. PD - L1 positivity of OSCC specimens served as the predictor variable and neck node metastasis as the primary outcome variable. Descriptive and inferential statistics were computed and the significance level was set at p ≤ 0.05.ResultsThe study sample was composed of 88 patients (male: 48, female: 40, mean age: 61.34 years). Significant PD - L1 expression was detected in 29% of the OSCC specimens (26/88) and 83% (73/88) of the specimens exhibited a high rate of PD - 1 positive TIL infiltration. PD - L1 positivity of OSCC samples was significantly associated with the anatomic origin of OSCC (p = 0.039), the presence of cervical metastasis (p = 0.039) and high PD - L1 positive TIL infiltration (p = 0.033).ConclusionA considerable proportion of OSCCs show significant PD - L1 expression. This may be associated with clinical parameters. PD - L1 expression in OSCC might differ depending on its anatomic origin. PD - 1 positive TILs can be detected in most OSCC specimens. These findings might indicate a potential role of the PD - 1/PD - L1 pathway in OSCC.



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