Best Practice PD-L1 Staining and Interpretation in Gastric Cancer Using PD-L1 IHC PharmDx 22C3 and PD-L1 IHC PharmDx 28-8 Assays, with Reference to Common Issues and Solutions.

ABSTRACT: Programmed death-ligand 1 (PD-L1) biomarker testing in gastric cancer is required to identify patients suitable for immunotherapy. However, the PD-L1 testing landscape is complex, with various PD-L1 tests available and multiple algorithms that combine tumor and immune cell staining. To provide guidance on the best practices for PD-L1 testing in gastric cancer, we reviewed the literature and incorporated our extensive experience using the PD-L1 IHC PharmDx 22C3 and 28-8 assays and scoring with the combined positive score (CPS) algorithm. This review summarizes inter-reader agreement and PD-L1 assay concordance studies in gastric cancer, highlights practical challenges and pitfalls encountered in our own laboratory, and proposes solutions to address them. Accurate and consistent interpretati

SUBMITTER: Ahn S 

PROVIDER: S-EPMC12649831 | biostudies-literature | 2025 Nov

REPOSITORIES: biostudies-literature