PDL1negativa

PD-L1 negativa refers to the absence or very low expression of the PD-L1 protein on tumor cells and/or tumor-infiltrating immune cells as detected by immunohistochemistry (IHC). The term may appear as PD-L1 negative or PD-L1(-) in different language contexts. Detection is performed on tissue samples using validated IHC assays, with several antibodies and scoring systems in use depending on tumor type and regulatory approvals. A result is considered negative when the expression falls below the assay-specific threshold, which varies by cancer type and testing method.

In clinical practice, PD-L1 status is used as a predictive biomarker for response to therapies that target the PD-1/PD-L1 axis. Generally, PD-L1 negative tumors show lower response rates to single-agent PD-1 or PD-L1 inhibitors compared with PD-L1 positive tumors; however, responses can still occur in PD-L1 negative cases. Therefore, PD-L1 negativity does not automatically exclude immunotherapy, especially in combination regimens or in settings where other therapeutic options exist. The interpretation of PD-L1 status is also influenced by tumor type and other biomarkers, such as mismatch repair deficiency, microsatellite instability, or tumor mutational burden.

PD-L1 expression is dynamic and heterogeneous. Expression can change over time, be influenced by prior treatments, and vary within different regions of the same tumor. Technical factors, including tissue handling and the specific assay used, can affect results. Consequently, PD-L1 negativity should be considered alongside clinical context, tumor type, and the chosen therapeutic strategy.