Tumor Markers

A tumor marker is any substance in your body that provides information about a cancer. Usually, it’s a protein that cancer cells make. But noncancerous cells can also make these substances in response to cancer.

A tumor marker may also refer to mutations (changes) or patterns in tumor cell DNA.

Other names for tumor markers are cancer markers and biomarkers.

Healthcare providers do tests to check for them. These tests help providers:

• Diagnose certain types of cancer: Different cancer types produce different markers.
• Plan treatment: Treatments may only work on cancers with certain biomarkers. For instance, targeted therapies only work on cancers with specific mutations in tumor cell DNA.
• Predict your chance of recovery: Some tumor markers are signs that the disease will be more (or less) challenging to treat.
• Check whether cancer treatments are working: A drop in tumor marker levels may mean treatment is working. An increase may mean the cancer has spread or come back.
• Screen for cancer: If you’re considered high risk for a certain type of cancer, a provider may recommend tumor marker tests to check for signs of disease. Cancer screening can’t diagnose disease alone, though. You’ll need more tests if screening is positive to verify the presence of a tumor.

Tumor markers provide one piece of information that providers may use to diagnose, treat, monitor and screen for cancers. But tumor markers can’t tell you everything about your diagnosis. For one thing, many cancers don’t have known tumor markers. And some noncancerous conditions make the same markers that cancers do.

These are just some reasons why providers often check for tumor markers alongside other tests to get a clearer picture of your health.

Types

There are two main types of tumor markers:

• Circulating tumor markers: Found in blood, urine (pee), stool (poop) or bone marrow
• Tumor tissue markers: Found in the actual tumor in your body tissue

​How does a tumor marker test work?

It depends on the type of cancer your healthcare provider tests for. These tests typically require one of the following:

• Blood test
• Saliva (spit) test
• Urinalysis (pee test)
• Stool (poop) test
• Biopsy

Most of these tests check fluid for circulating tumor markers. Among circulating markers, blood tests are most common. A liquid biopsy is an example of a test that checks for biomarkers in blood.

A biopsy removes and tests for tissue markers. It can also check for tumor markers in fluid. For instance, a bone marrow biopsy can check for tumor markers in the tissue and liquid parts of bone marrow.

Common cancer tumor markers

There are lots of tumor markers. Some are associated with just one cancer, while others are linked to many different types. Here are just a few of the most common ones:

The number of tumor markers will grow as researchers identify more kinds and more ways to use them to aid in cancer diagnosis and treatment.

What do test results look like?

There are many different cancer markers, each with its own normal range. What’s considered a “high” or “low” level can vary from person to person. Results can also vary based on when you take the test.

This is why your healthcare provider is your best resource for knowing what your results mean for your health.

What does it mean when tumor markers are high?

High tumor marker results might suggest the presence of cancer. They may also suggest that cancer has progressed or spread. But this test alone isn’t enough to diagnose cancer. For example, noncancerous conditions may cause high values in some cases, too.

Your healthcare provider will explain what the numbers mean.

What does it mean when tumor markers go down?

If tumor markers go down, it could mean treatment is working. Still, tumor markers can go up and down over time, even over the course of your treatment. For this reason, it can be difficult to measure them consistently.

This is why healthcare providers use tumor marker tests in combination with other tests.

​Follow-up

Your healthcare provider will follow up with you to explain your test results. You could receive blood, urine, stool or saliva test results within a day or two. If you need a biopsy, it could take a week or longer to get your results.

Your provider will tell you next steps based on your results.

Can noncancerous conditions cause tumor markers to rise?

Yes. Several things can cause tumor markers to rise. This includes noncancerous conditions. It also includes everything from medications and procedures to high stress levels and even certain foods.

This is why it’s important not to assume the worst just because a test finds high levels.