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Published on: February 3, 2023
Development of a Prototype Immunohistochemistry Assay to Measure Programmed Death Ligand-1 Expression in Tumor Tissue
Marisa Dolled-Filhart1, Darren Locke, Tiffany Murphy
1From the Departments of Molecular Biomarkers and Diagnostics (Drs Dolled-Filhart, Pierce, Weiner, Wu, and Emancipator) and Profiling and Expression (Dr Yearley), Merck & Co, Inc, Kenilworth, New Jersey; the Departments of Early Clinical & Translational Research, Clinical Histochemistry (Dr Locke), Research and Clinical Client Services (Dr Murphy), and Operations and Client Services (Dr Lynch), QualTek Molecular Laboratories, Newtown, Pennsylvania; and the Department of Pathology, Eisenhower Medical Center, Rancho Mirage, California (Dr Frisman). Dr Locke is now with Bristol-Myers Squibb, Princeton, New Jersey; Dr Pierce is now with OncoSec Medical, Inc, San Diego, California; Dr Weiner is now with Daiichi Sankyo, Edison, New Jersey; and Dr Wu is currently at Janssen Research & Development, Spring House, Pennsylvania.
A new immunohistochemistry assay using the anti-PD-L1 antibody 22C3 was developed. This assay shows promise for identifying patients likely to respond to PD-L1 targeted therapies in lung cancer and melanoma.
Area of Science:
- Oncology
- Immunology
- Pathology
Background:
- Targeted therapies against programmed death receptor-1 (PD-1) and its ligand (PD-L1) are abundant.
- Identifying patients likely to respond to these therapies is crucial.
- PD-L1 expression may indicate an inflammatory response and predict therapy response.
Purpose of the Study:
- To develop a prototype immunohistochemistry (IHC) assay.
- Utilize the anti-PD-L1 antibody clone 22C3 for assay development.
Main Methods:
- The IHC assay was developed and optimized using commercially available reagents.
- Archival tumor-bank tissue samples were used for optimization and validation.
- The assay was tested on 142 non-small cell lung cancer (NSCLC) and 79 melanoma samples.
Main Results:
- The optimized IHC method demonstrated high precision and reproducibility.
- PD-L1 staining was observed on tumor and non-tumor cells, and at the tumor-stroma border.
- 56% of NSCLC and 53% of melanoma samples were PD-L1 positive using a preliminary scoring method.
Conclusions:
- The IHC assay with anti-PD-L1 antibody 22C3 warrants further investigation.
- Clinical trials and prevalence assessments are needed.
- Further research will clarify the prognostic and predictive value of PD-L1 expression in cancer.
