Effect of Dual PD-L1 Staining on PD-L1 Scoring in Non-Small Cell Lung Carcinomas
Key Clinical Takeaways
- Design/Population: As presented at the 2025 American Society for Clinical Pathology (ASCP) Annual Meeting in Orlando, Florida, a study of 14 NSCLC cytology cases, including pleural fluid and lung FNA specimens, compared dual PD-L1 staining (TTF-1/PD-L1 or p40/PD-L1) with mono PD-L1 staining.
- Key Outcomes: No significant differences were found in PD-L1 scoring between methods (P = .67 vs original; P = .66 vs consensus); Bland-Altman plots showed nearly all scores within 95% limits of agreement.
- Clinical Relevance: Dual PD-L1 staining did not alter scoring results but was easier to interpret, potentially increasing reader confidence though with added cost considerations.
A study found, while dual PD-L1 staining may be easier to interpret, there was no significant impact on PD-L1 scoring with dual staining, when compared to mono staining.
These data were first presented by Tammi Holle, MD, Medical College of Wisconsin, Milwaukee, Wisconsin at the American Society for Clinical Pathology 2025 Annual Meeting in Orlando, Florida.
Dr Holle and coauthors explained that interpretation of PD-L1 staining can be challenging with mono PD-L1 staining, as this method also labels macrophages. However, “dual stain with TTF-1/PD-L1 or p40/PD-L1 can distinguish PD-L1 positive tumor cells from macrophages.”
This study included 14 NSCLC cytology cases, with both pleural fluid and lung fine need aspirations (FNA), between 2021 and 2024. There were 9 cases of adenocarcinoma and 5 cases of squamous cell carcinoma. Tumor proportion score (TPS) for the were assessed for the specimens by 4 pathologists, blinded to the original PD-L1 results. Dual stains were performed with TTF-1/PD-L1 for adenocarcinoma cases and with p40/PD-L1 for squamous cell carcinoma cases. Bland-Altman plots were used to assess agreement of scoring within the upper and lower 95% limits of agreement.
There was no significant difference between the original results and the consensus PD-L1 (P = .67). There were 2 scores which fell outside of the upper- and lower- 95% limits of agreement (1 above upper-limit, 1 below lower-limit) on the Bland-Altman plot. There was also no significant difference seen between the consensus and the dual PD-L1 (P = .66). No scores fell outside the upper- or lower- 95% limits of agreement on the Bland-Altman plot.
Dr Holle et all concluded, that dual PD-L1 staining compared to mono staining “does not have a significant impact on PD-L1 scoring and may not be worth the additional cost.” However, the dual stain “was easier to interpret which may increase confidence in PD-L1 scoring.”
Source:
Holle T, Puzyrenko A, Hunt B, and Giorgadze T. Performance of dual PD-L1 staining in non-small cell lung carcinoma. Presented at ASCP 2025 Annual Meeting. November 17-20, 2025; Orlando, Florida.
