Abstract 4037: Analytical and inter-observer comparability of 4 clinically developed programmed death-ligand 1 (PD-L1) immunohistochemistry assays in advanced clear cell renal cell carcinoma (CCRCC)

Background: PD-L1/programmed cell death-1 (PD-1)-targeting checkpoint inhibitors have shown clinical activity in advanced and metastatic RCC, which correlates with PD-L1 expression on tumor cells (TC) and/or tumor-infiltrating immune cells (IC). We examined the analytical performance and inter-observer agreement of 4 clinically developed assays for PD-L1 expression on IC and TC in locally advanced CCRCC. Methods: Archived formalin-fixed...