Professional
Technical
IVT
PD-L1 expression
Pronunciation: P-D-L-one
Also written as: PD-L1 — Programmed Death-Ligand 1
The level of programmed death-ligand 1 protein on tumor cells, used to predict response to immunotherapy.
Full Definition
PD-L1 expression is measured by immunohistochemistry and reported as a tumor proportion score (TPS), representing the percentage of viable tumor cells showing membrane staining. High PD-L1 expression (typically ≥50% TPS) correlates with better response to PD-1/PD-L1 inhibitors like pembrolizumab. Different antibodies and scoring systems exist, making standardization important for treatment decisions.
Usage
Usage note: Always hyphenate PD-L1. Use 'expression' not 'positivity' for professional accuracy.
In Context
- "PD-L1 expression was 60% by tumor proportion score." — Pathology report
- "High PD-L1 expression supports first-line pembrolizumab monotherapy." — Treatment recommendation
Also known as
PD-L1 status
programmed death-ligand 1 expression
Contrasted with
PD-L1 negative
Don't confuse with
PD-1 expression
PDL1