Tests
PDL1 (Immunotherapy) Tests
A PD-L1 test uses a sample of cancerous tumor tissue to measure how much of a protein called programmed-death ligand 1 (PD-L1) is found on the cancer cells. Normally, PD-L1 is found on certain healthy cells. It helps keep your immune system from attacking healthy tissue by acting as a kind of "brake" on your immune system cells (called T-cells). However, in some cancers, PD-L1 keeps your immune system from attacking cancerous cells.