Comparison of patient populations identified by different PD-L1 assays in head and neck squamous cell carcinoma (HNSCC)

Abstract

Methods: Four immunohistochemistry (IHC) assays: VENTANA PD-L1 (SP263), VENTANA PD-L1 (SP142), PD-L1 IHC pharmDx 22C3 (Agilent) and PD-L1 IHC pharmDx 28-8 (Agilent) were used to stain 486 HNSCC samples. In a new analysis of previously stained samples (Ratcliffe Ann Onc 2016;27:955D), all slides were scored by a single pathologist to eliminate inter-reader variability. Positive (PPA), negative (NPA) and overall (OPA) percent agreement are newly reported between various tumour cell (TC), immune cell (IC) and combined positive score (CPS) cutoffs.