Research
What Is Biomarker Testing for Cancer Treatment?
You'll hear about biomarker testing, tumor profiling, and 'matching' treatments to a person's cancer. Here's what biomarker testing is and how it guides treatment choices.
Please note: this page is educational only — it is not medical advice, and it does not speculate about anyone’s health beyond reliable public reporting. For questions about your own health, talk with your healthcare team.
What people see in the news
Coverage of new cancer drugs often mentions "biomarker testing," "tumor profiling," or treatments that only work if a person's cancer has a certain gene change. It can sound highly technical. In plain terms, it's about finding clues in a tumor that help guide treatment.
What it actually means
According to the National Cancer Institute, biomarker testing is a way to look for genes, proteins, and other substances (called biomarkers or tumor markers) that can provide information about cancer. Each person's cancer has a unique pattern of biomarkers, and some of them affect how certain treatments work.
NCI explains that biomarker testing may go by other names too — tumor testing, tumor genetic testing, genomic or molecular profiling, or somatic testing. It's for people who already have cancer, and it's different from genetic testing that looks for inherited mutations you were born with.
NCI notes that some treatments, including targeted therapies and immunotherapies, may only work for people whose cancers have certain biomarkers. For example, cancers with certain changes in the EGFR gene can be treated with drugs called EGFR inhibitors. Biomarker testing can also help someone find a clinical trial to join.
NCI is candid that biomarker tests don't help everyone. A test might not find a matching therapy, there might not be enough tumor tissue, or a matched treatment might not be covered by insurance. And even when a biomarker matches a treatment, NCI notes the therapy may not work — partly because not all of a person's cancer cells carry the same biomarkers, and because biomarkers can change over time.
What to keep in mind
- Biomarker testing is for people who have cancer; it's not the same as inherited-risk genetic testing.
- NCI describes biomarker testing as an important part of precision medicine, while also noting the "standard" approach to treatment is effective and personalized too.
- A biomarker result is a snapshot in time, so doctors may retest — for example, if cancer comes back.
Questions to ask a healthcare team
- Should biomarker testing be part of my care, and is it available where I'm treated?
- What would the results change about my treatment options?
- Could testing help me find a clinical trial?
- Will my insurance cover the test?
Understanding biomarker testing helps make sense of the many "targeted" and "personalized" treatment stories in the news. Free, plain-language cancer education helps more people follow along.