PD-L1 Immunotherapy Response Test - Immunohistochemistry (IHC) for PD-L1

Immunohistochemical assay (IHC) measures the expression level of PD-L1 (Programmed Death-Ligand 1) protein on the surface of cancer cells or immune cells within a tumor. PD-L1 protein binds to the PD-1 receptor on T cells, suppressing the immune response against the tumor. This assay is used as a predictive marker for selecting patients who are candidates for immunosuppression therapies (such as atezolizumab and pembrolizumab).