Biomarkers and Cancer: Do They Matter for Me?

This article is for people who want to understand how biomarkers may affect their cancer treatment choices. It's also for their care partners, and others who want to learn more about the topic. The goal is to help you know what to discuss with your healthcare team about testing for biomarkers and what the results mean for your treatment.

You'll explore

• What biomarkers are and how they show changes in your cancer cells

• Which tests your provider may order to find certain biomarkers

• How immunotherapy offers another treatment option for certain cancers with specific biomarkers

• What questions to ask your healthcare provider about biomarker testing and what the results may mean for you

A biomarker is a sign of health or disease in your body that can be measured. For example, your blood pressure and body temperature are biomarkers. Cancer biomarkers are usually proteins or genes that affect cancer cells.

Some biomarker tests check for changes in your cancer cells. Knowing if you have certain biomarkers helps your healthcare provider know which cancer treatments may work best for you. This helps you and your provider decide on a treatment plan.

After you complete this activity, talk with your healthcare provider about whether biomarker testing is an option for you.

Biomarker tests are sometimes called molecular or genomic tests.

To help plan your cancer treatment, your healthcare provider may order tests that look for various biomarkers.

Two of the major biomarkers in immunotherapy are:

• Programmed death ligand-1 (PD-L1)

• Microsatellite instability (MSI)

Your healthcare provider may use PD-L1 and/or MSI testing for colorectal, bladder, gastric, cervical, non-small cell lung cancer, and other types of cancer.

A PD-L1 and/or an MSI test may help your provider decide if a medicine called an immune checkpoint inhibitor (a type of immunotherapy) would be a good treatment for you. Immunotherapy is a cancer treatment that uses your body's immune system to get rid of cancer cells.

Other biomarkers are being studied in clinical trials and may open doors for potential new treatment options.

Programmed cell death 1 (PD-1) and PD-L1 are proteins on cells in your body.

PD-1 on immune "T" cells makes them "smart cells" that know not to attack healthy cells that have PD-L1. Cancer cells can also have large amounts of PD-L1, which tricks your immune cells by signaling them not to attack.

Immune checkpoint inhibitors stop cancer cells from tricking your immune system. They block PD-1 or PD-L1 and break the signal. Your immune cells can then do their job and attack the cancer cells.

This table shows PD-1 or PD-L1 immune checkpoint inhibitors your provider may prescribe alone or in combination with other medicines.

Medicine	Cancer Type
Pembrolizumab (Keytruda®)	Non-small cell lung (nonsquamous)Squamous cell head and neckBladderGastric, esophageal
Nivolumab (Opdivo®)	Non-small cell lung (nonsquamous)Squamous cell head and neck
Atezolizumab (Tecentriq®)	Non-small cell lung cancer (nonsquamous)Bladder
Durvalumab (Imfinzi®)	Bladder
Avelumab (Bavencio®)	Merkel cell carcinoma

Mistakes sometimes happen when our cells divide. So we have proteins called mismatch repair (MMR) that "autocorrect" these mistakes. But we can have defects (mutations) in our MMR genes.

An MSI (stands for microsatellite instable) test looks for MMR defects (called dMMR) in your cancer cells. A high amount of instability (many defects) is called MSI-High or MSI-H. MSI-H may be found in some colorectal and several other types of cancer.

If your cancer cells have MSI-H (or dMMR), immunotherapy maybe a good treatment option for you.

Pembrolizumab -- approved to treat people who have MSI-H or dMMR solid tumors -- regardless of the tumor's location -- that have progressed after one standard of care treatment and who have no other good treatment options.

Nivolumab -- approved to treat people who have MSI-H or dMMR metastatic colorectal cancer that's progressed after one prior standard of care treatment and who have no other good treatment options.

Nivolumab plus ipilimumab (another type of cancer medicine) -- recently was approved treatment for people with MSI-H or dMMR metastatic colorectal cancer that's progressed after other treatment. Ipilimumab blocks cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), another cell protein.

Your healthcare provider will take a sample of your cancer cells (either blood or tumor tissue) and send it to a lab that does biomarker testing. The lab will test the sample to find out if your cancer cells have specific biomarkers and, if so, at what level. Your provider will get your results within a few weeks. Then you and your care team can discuss a treatment plan based on your cancer's biomarker profile.

Ask a member of your team about financial assistance programs if

• You're uninsured or biomarker tests are not covered by your health plan

• You have insurance but can't afford out-of-pocket costs for the tests

These questions may help you talk to your provider about biomarker testing:

• Should I have biomarker testing to plan my cancer treatment?

• When should I get tested?

• Are molecular (or genomic) tests the same as genetic tests?

• What do my test results mean?

• What if I don't have MSI-H or PD-1/PD-L1? What other treatment options do I have?

• Are there any clinical trials that may be right for me?

Congratulations!

You have successfully completed the program: Biomarkers and Cancer: Do They Matter for Me?