CD274 and head and neck squamous cell carcinoma: Müller Müller T T Braun Braun M M Dietrich Dietrich D D Aktekin Aktekin S S Höft Höft S S Kristiansen Kristiansen G G Göke Göke F F Schröck Schröck A A Brägelmann Brägelmann J J Held Held SAE SAE Bootz Bootz F F Brossart Brossart P P PD-L1: a novel prognostic biomarker in head and neck squamous cell carcinoma PD-L1: a novel prognostic biomarker in head and neck squamous cell carcinoma Oncotarget Oncotarget 2017 2017 8 8 32 32 52889 52889 52900 52900 10.18632/oncotarget.17547 10.18632/oncotarget.17547 supplied-pmid 28881780?