Pancreatic Cancer: Biomarker Testing

Biomarker Testing for People with Pancreatic Cancer

This section covers the following topics:

• Tumor biomarker testing
• Biomarker tests for treatment selection 
• Biomarker tests for disease monitoring
• Genetic testing for treatment selection

What is pancreatic cancer biomarker testing?

Biomarker tests look at samples of blood, tumor or other tissue for changes or abnormalities caused by cancer. These tests can give doctors clues about the cancer, including:

• how fast the cancer is growing
• which treatments are most likely to work
• whether or not the cancer is responding to treatment or growing
• whether or not the cancer has come back after remission

Biomarker tests may be used to select treatments, and help patients avoid side effects from treatments that will not work for them. Biomarker tests used to select a specific treatment are sometimes called companion diagnostic tests. These tests may be done on tumor tissue or (in some cases) on blood. See our Biomarker Testing section for more information. 

Biomarkers for treatment selection

Examples of biomarker tests used for pancreatic cancer include:

• Some pancreatic cancers will have an abnormality known as MSI-high (microsatellite instability-high) also known as "mismatch repair deficiency" (dMMR or MMR-D). MSI-high cancers are common in people with a Lynch syndrome gene mutation. These cancers may respond well to a type of treatment known as an immune checkpoint inhibitor. One example of an immunotherapy agent used for MSI-H cancers is Keytruda (pembrolizumab).
• HER2-positive tumors may respond to treatment with Enhertu (trastuzumab deruxtecan). 
• Tumors that test positive for a RET gene fusion may respond to the drug Retevmo (selpercatinib). 
• A biomarker known as an NTRK fusion can  predict who might benefit from the targeted therapy Vitrakvi (larotrectinib).
• Additional tumor biomarker testing may help people learn if they are eligible for certain clinical trials. 

Biomarkers to monitor recurrence or response to treatment

CA19-9 is a type of protein that is produced in large amounts by some pancreatic cancers. Doctors may use CA19-9 blood tests monitor recurrence or response to treatment. 

Clinical trials are studying whether other blood tests known as liquid biopsies can be used to detect recurrence in people who have completed treatment for pancreatic cancer.  These tests check the blood for abnormal DNA from tumor cells (known as circulating tumor DNA or ctDNA).

Genetic testing for inherited mutations to guide treatment selection

All people diagnosed with pancreatic cancer should be offered genetic testing for an inherited mutation. Genetic test results  may be used to guide treatment selection.  

• People who test positive for an inherited BRCA1 or BRCA2 mutation may respond better to a treatment regimen that includes a type of chemotherapy known as platinum. They may also benefit from maintenance therapy with a type of targeted therapy known as a PARP inhibitor.  
• People who test positive for other inherited gene mutations may qualify for clinical trials looking at targeted therapies. 
• People who test positive for a Lynch syndrome gene mutation may benefit from treatment with an immunotherapy agent. 
• People who test positive for a Lynch syndrome gene mutation may benefit from treatment with an immunotherapy agent.