The immune checkpoint regulator PD-L1 is highly expressed in aggressive primary prostate cancer

PURPOSE - Therapies targeting the programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) pathway promote anti-tumor immunity and have shown promising results in various tumors. Preliminary data further indicate that immunohistochemically detected PD-L1 may be predictive for anti-PD-1 therapy.

So far, no data are available on PD-L1 expression in primary prostate cancer.

EXPERIMENTAL DESIGN - Following validation of a monoclonal antibody, immunohistochemical analysis of PD-L1 expression was performed in two independent, well-characterized cohorts of primary prostate cancer patients following radical prostatectomy (RP), and resulting data were correlated to clinicopathological parameters and outcome.

RESULTS - In the training cohort (n=209), 52. 2% of cases expressed moderate to high PD-L1 levels, which positively correlated with proliferation (Ki67, p

CONCLUSIONS - We provide first evidence that expression of the therapy target PD-L1 is not only highly prevalent in primary prostate cancer cells but is also an independent indicator of BCR, suggesting a biological relevance in primary tumors. Further studies need to ascertain, if PD-1/PD-L1 targeted therapy might be a treatment option for hormone-naive prostate cancers.

Clinical cancer research : an official journal of the American Association for Cancer Research. 2015 Nov 16 [Epub ahead of print]

Heidrun Gevensleben, Dimo Dietrich, Carsten Golletz, Susanne Steiner, Maria Jung, Thore Thiesler, Michael Majores, Johannes Stein, Barbara Uhl, Stefan Mueller, Joerg Ellinger, Carsten Stephan, Klaus Jung, Peter Brossart, Glen Kristiansen

University of Bonn. , Institute of Pathology, University Hospital Bonn. , Institute of Pathology, University Hospital Bonn. , Department of Pathology, University of Bonn Medical Center. , Institute of Pathology, Center for Integrated Oncology, University of Bonn. , Institute of Pathology, University of Bonn. , Institute of Pathology. , Institute of Pathology. , Institute of Pathology, Center for Integrated Oncology, University of Bonn. , Department of Urology, University of Bonn. , Klinik und Poliklinik für Urologie, Universitätsklinikum Bonn. , Department of Urology, Charité Universitatsmedizin Berlin. , Res Div, Dept Urol Humboldt University. , Department of Internal Medicine III, Oncology, Hematology and Rheumatology, University Clinic Bonn (UKB). , Institute of Pathology, Center for Integrated Oncology, University of Bonn Glen. 

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