What is biomarker testing?

Biomarker testing looks for features of a cancer that may help your care team understand it and consider treatment options.

Some tests examine genes in cancer cells; others look at proteins or other features. Testing does not always find something that changes treatment — but it can sometimes identify findings relevant to treatment or clinical-trial options.

This page is general information, not medical advice. Advice from your own care team comes first.

On this page: Three tests that are often confused · What testing looks for · Tumour vs inherited testing · How a sample is obtained · What results may mean · When results don't change treatment · Questions to ask · Testing in Canada

Three tests that are often confused

• Tumour biomarker testing — examines features of the cancer itself that may help inform treatment or trial options. It is usually done on a sample of the tumour.
• Inherited genetic testing — looks for gene changes you were born with, using a blood or saliva sample. Results may matter for your care and for your relatives.
• CA19-9 blood testing — measures a tumour marker in the blood that may help monitor pancreatic cancer. It is not the same as molecular profiling, and it cannot diagnose pancreatic cancer by itself.

People sometimes use “biomarker testing,” “genomic testing,” and “molecular profiling” interchangeably. On this page, biomarker testing means testing the cancer for features that may guide care.

What biomarker testing looks for

Testing can look for changes in the cancer's genes, for particular proteins, or for other measurable features. Some findings are relevant to particular treatments; some are relevant to clinical trials; some help the care team understand the cancer better without pointing to a specific treatment.

Eligibility for a treatment depends on more than a gene name alone — the specific finding, the type and stage of cancer, previous treatments, and your overall health all matter.

Tumour testing and inherited testing are different

A test performed on tumour tissue can find a change that is either acquired — developed in the cancer — or potentially inherited. Tumour testing alone cannot always tell which. If a tumour result raises the possibility of an inherited change, further testing of a blood or saliva sample (germline testing) may be recommended to clarify it.

That distinction matters twice over: an inherited change can affect your own care, and it can also be relevant to your blood relatives, who may be offered testing and counselling of their own.

How a sample is obtained

Tumour testing usually uses tissue that already exists — from a biopsy or from surgery — so a new procedure is often not needed. The laboratory checks whether the sample has enough tumour tissue to test.

Blood-based tumour testing may be considered in some circumstances. It is not an interchangeable replacement for tissue testing, and your care team can explain whether it is appropriate in your situation.

What results may mean

When results come back, they may:

• Suggest treatment considerations to discuss with your care team.
• Make a clinical-trial referral relevant.
• Indicate that inherited genetic testing or genetic counselling should follow.
• Recommend no immediate change — while still informing future options.

Ask who will explain the results to you, and what happens next in each case.

Why a result may not change treatment

There are several ordinary reasons:

• The testing did not find a feature linked to a different treatment.
• A relevant treatment exists but is not approved or publicly funded for your situation, or is not available where you are treated.
• The sample did not contain enough tumour tissue, and testing could not be completed.
• Your overall health or treatment history means the option is not suitable right now.

A result that changes nothing today can still matter later — treatment options and trial openings change over time.

Questions to ask your care team

• Has my tumour already been tested?
• What testing is appropriate for my diagnosis and treatment situation?
• Is there enough tissue from my existing biopsy?
• Have I also been offered inherited genetic testing?
• Who will explain the results?
• Could the results affect treatment or trial options?
• Is the recommended testing publicly funded in my circumstances?

These are conversation starters — not a promise that every test is appropriate or covered.

Testing in Canada

Access to biomarker testing varies by province. Some provinces run publicly funded programs — Ontario's comprehensive biomarker testing program, for example, is publicly funded province-wide. In other provinces, testing may involve samples sent to another province, and turnaround times vary. A national pilot, My CANcer Code (Pancreatic Cancer North America, with OncoHelix), offers free comprehensive testing to eligible patients across Canada.

The Foundation's policy work on this — what we are asking the system to change — is on our Equitable access to biomarker testing page. For the wider picture of testing in pancreatic cancer care, see Testing in pancreatic cancer and our guide to genetic testing for pancreatic cancer.

Sources

• Biomarkers and genetic testing — MyPathologyReport
• Pancreatic cancer awareness with Dr. Jennifer Knox — University Health Network (tumour vs germline testing)
• The role of molecular testing in pancreatic cancer (review)
• Targeted therapy for pancreatic cancer — Canadian Cancer Society
• BRCA gene changes: cancer risk and genetic testing — U.S. National Cancer Institute

Last reviewed: October 24, 2026. Spotted something out of date? Report it here.