Review articlePD-L1 IHC in NSCLC with a global and methodological perspective

- PD-L1 IHC is biomarker for treatment with PD-1 checkpoint immunotherapy in NSCLC.
- Each PD-(L)1 checkpoint inhibitor has been validated with a different PD-L1 IHC assay.
- Preferably one affordable, clinically validated PD-L1 IHC test is needed.
- Selection of critical samples is crucial for validation of PD-L1 IHC assay.

In summary, the PD-L1 biomarker discussed here highlights the importance of understanding the practice of IHC. This can be used to the patients advantage, with appropriate usage. The currently available literature on PD-L1 IHC from a methodologic point of view has not shown that different assays are comparable. The route of laboratory developed test and commercial test validation is the same: challenging and complex. Executing this process along proper methodologic lines is needed to ensure that patients receive the most accurate and representative test outcomes.