Ovarian Cancer: Biomarker Testing

Biomarker Testing for People with Ovarian 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 ovarian 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 many cases) on blood. See our Biomarker Testing section for more information. 

Common biomarkers for treatment selection

Examples of biomarker tests used for ovarian, fallopian tube and primary peritoneal cancer include:

• Tests can be done to look for BRCA1 or BRCA2 gene mutations in the tumor. Women who test positive for a BRCA1 or BRCA2 mutation in their tumor may benefit from a type of therapy known as a PARP inhibitor. A tumor test positive for a BRCA1 or BRCA2 mutation in one of two situations:, 
  • when people who have an inherited mutation in BRCA1 or BRCA2 develop cancer, their tumor is very likely to display the same mutation.
  • people who test negative for an inherited mutation in BRCA1 or BRCA2 may still develop an acquired BRCA mutation in their tumor. People with a BRCA mutation in their tumor may also respond well to PARP inhibitor treatment.  
• A tumor test for a marker called HRD (homologous recombination deficiency) can help people with advanced ovarian cancer learn if they may benefit from maintenance therapy with a PARP inhibitor.  
• Some ovarian 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).
• A biomarker called FRα-positive (folate receptor alpha) may predict which people with advanced or recurrent ovarian cancer will benefit from treatment with a drug called ELAHERE (mirvetuximab soravtansine-gynx).

Less common biomarkers for treatment selection

• 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

CA125 is a type of protein that is produced in large amounts by some ovarian cancers. Doctors may use CA125 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 ovarian 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 ovarian cancer should be offered genetic testing for an inherited mutation. Genetic test results  may be used to guide treatment selection for people diagnosed with ovarian cancer.  

• People with advanced ovarian cancer who test positive for an inherited BRCA1 or BRCA2 mutation may benefit from treatment 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 to treat hereditary ovarian cancer. 
• People who test positive for a Lynch syndrome gene mutation may benefit from treatment with an immunotherapy agent.