Ovarian Cancer: Testing Times

A biomarker is a distinct biochemical, genetic, or molecular characteristic that’s an indicator of a particular biological condition. Biomarkers can include any chemical substance in the body (such as a protein, a gene, or a fatty acid) that help us to:

• Understand the cause and behaviour of a particular disease
• Know a person’s risk of developing a disease
• Diagnose a disease
• Predict the outcome and response to treatment

Certain genetic mutations are biomarkers. For example, women with disease-causing mutations in the genes BRCA1 and BRCA2 have a significantly higher chance of developing breast, ovarian and other cancers than women who do not carry these gene variants.

Women with disease-causing variants in BRCA1 and BRCA2 may be eligible for treatment with personalised medicines, which target their specific form of ovarian cancer.

Tumour testing can provide information about choices of treatment that can be used at the time of diagnosis and if the cancer comes back. If you’ve been newly diagnosed with ovarian cancer, it’s very important to know whether you carry a hereditary or non-hereditary mutation inside your tumour. This information will identify whether you may be eligible for treatment with certain precision medicines or targeted treatments for your specific tumour type.

If you carry a hereditary mutation in your BRCA1 or BRCA2 genes (or in other genes such as RAD51C, RAD51D, BRIP1, PALB2, MLH1, MSH2, MSH6, PMS2), your blood relatives may also be carriers. A blood test will confirm if they carry the same gene mutation. This is important because treatment can then be offered to reduce their risk of ovarian (and breast) cancer.

There are currently two methods of BRCA (and other gene) testing:

1. Germline testing – undertaken on blood samples to detect inherited disease-causing variants. Results can have implications for family members. 
2. Tumour testing – involves extracting DNA from a small piece of the ovarian tumour and testing it for disease-causing variants or mutations. 

Approximately two-thirds of mutations detected in tumours are inherited and nearly one-third are not inherited mutations.

Biomarkers can be hereditary but not always.

1. An example of a hereditary biomarker would be a disease-causing variant or mutation in the BRCA1/2 genes.
2. An example of non-hereditary biomarker is ‘somatic’ gene mutations, which are mutations and disease-causing gene variants that arise spontaneously in a tumour as it grows. These aren’t inherited from a parent and can’t be passed on to a child. These mutations occur only in the tumour, and not elsewhere in the body. Somatic (‘tumour only’) mutations can also occur in the BRCA1/2 genes.

The best time to have genetic tests is after your ovarian cancer diagnosis. The tests involve:

• Germline testing – A blood test to see if you’ve inherited a gene mutation or variant.
• Tumour testing – A small piece of tumour tissue is taken in a biopsy and sent to a molecular diagnostic laboratory to check whether there are genetic mutations in the tumour.

If your specialist team has recommended treatment with chemotherapy before surgery (neoadjuvant chemotherapy), it’s preferable to have a ‘core biopsy’ taken for tumour genetic testing. This won’t delay you starting chemotherapy.

A core biopsy involves a small piece of tumour being removed from your body under local anaesthetic while a CT scan is simultaneously performed to guide the biopsy needle. If you’re having, or have had, surgery at the start of your treatment (primary surgery) before chemotherapy, tumour tissue can be sent for tumour testing after surgery.

Ask your oncologist whether you’re eligible to have a tumour test to confirm your tumour type and determine your treatment options as these tests are not recommended for all types of ovarian cancer.

You can download our Tumour Test Checklist below.