CD274 and head and neck squamous cell carcinoma: 28881780 28881780 Müller T, Braun M, Dietrich D, Aktekin S, Höft S, Kristiansen G, Göke F, Schröck A, Brägelmann J, Held SAE, Bootz F, Brossart P (2017) PD-L1: a novel prognostic biomarker in head and neck squamous cell carcinoma.