Cells throughout the body make a type of protein called PD-L1. These proteins stick to receptors (PD-1s) on the surface of immune cells (T-cells) and stop the body’s natural immune system from attacking healthy cells. This is a healthy, supportive function that becomes detrimental when cancer hijacks it.
When PD-L1 proteins found on tumors stick to the PD-1 proteins on T-cells, it tricks them into stopping the search for cancer cells. This allows cancer to grow.
Biomarker testing can measure the amount of PD-L1 protein in a tumor. The measure will be called a Tumor Proportion Score (TPS) or a Combined Positive Score (CPS). Higher scores may indicate that a patient is a good candidate for the type of immunotherapy called “checkpoint inhibitors.”
Immunotherapy uses the body’s immune system to fight off cancerous cells. Immunotherapy drugs can disrupt the PD-L1/PD-1 interaction and help stop the signal telling the body’s T-cells to stand down. If a tumor has high amounts of PD-L1, it can be a strong target for immunotherapy drugs.
Gastric, esophageal, GEJ cancers (in advanced, specific situations)
Clinical trials for many other GI cancer types are also looking into the use of immunotherapy on patients based on their PD-L1 scores.
Your treatment plan will be unique and dependent on several factors. Ask your doctor how your biomarker test results are informing your treatment plan and if you qualify for any clinical trials.
