Intratumoral heterogeneity of PD-L1 expression in head and neck squamous cell cancers and its clinical relevance

Background In head and neck squamous cell carcinoma (HNSCC), the indication for PD-1 antibody therapy is based in part on the combined positive score (CPS) of PD-L1 expression. The absolute CPS is not decisive for the therapy decision, but the classification into the categories: CPS < 1, CPS 1 – 20, or CPS > 20. In this study, we investigated the heterogeneity of PD-L1 expression (CPS) within primary tumors (PT) as well as between PT and lymph node metastases (LNM) along with local recurrences (LR) in patients with HNSCC and its influence on clinical therapy decisions.