[Consistency comparison of programmed cell death 1-ligand 1 in different immuno-histochemical staining methods]

Area of Science:

• Immunohistochemistry
• Cancer Biomarkers
• Molecular Pathology

Context:

• Programmed cell death 1-ligand 1 (PD-L1) is a crucial biomarker in cancer immunotherapy.
• Standardized and reproducible PD-L1 detection is essential for patient stratification.
• Variations in immunohistochemical staining methods can affect PD-L1 expression results.

Purpose:

• To compare the consistency of programmed cell death 1-ligand 1 (PD-L1) detection using the E1L3N antibody across different immunohistochemical staining methods.
• To validate a self-built staining protocol against established standard procedures (22C3 and SP263).

Summary:

• A self-built immunohistochemical staining protocol (process ①) using PD-L1 clone E1L3N was optimized and evaluated on tonsil tissue, achieving the highest quality score.
• This optimized protocol was then applied to 32 non-small cell lung carcinoma (NSCLC) cases, and the resulting tumor proportion scores (TPS) were compared with those obtained using standard 22C3 and SP263 procedures.
• The self-built protocol demonstrated good agreement with the 22C3 standard (κ=0.736) and very good agreement with the SP263 standard (κ=0.914).

Impact:

• Establishes a validated, high-quality self-built staining protocol for PD-L1 (E1L3N) detection on the Ventana Benchmark GX platform.
• Provides evidence that this protocol yields consistent results comparable to widely used standard methods.
• Supports the reliable use of PD-L1 (E1L3N) testing for patient selection in NSCLC treatment.