[PD-L1 expression in squamous cell carcinomas of the upper aerodigestive tract: Pathological challenges and...

PD-L1 immunohistochemical assessment has become an essential biomarker in the management of squamous cell carcinomas of the upper aerodigestive tract (UADT). The Combined Positive Score (CPS) is currently the gold standard method for quantifying PD-L1 expression. This article provides an update on the technical and interpretative aspects of the CPS, practical recommendations for pathologists, and associated therapeutic implications. Particular attention is paid to challenges such as reproducibility of scoring, antibody selection, and the integration of PD-L1 expression data in therapeutic decisions, especially in the context of immunotherapy. The objective is to provide pathologists with an up-to-date synthesis of best practices and to give clinicians a better understanding of the role of PD-L1 in the personalized management strategy for patients with UADT squamous cell carcinoma.