10/26/2026
Even people with the same type of cancer can have important differences in their cancer cells. That’s one reason biomarker testing can be an important part of cancer care.
Biomarker testing looks for specific genes, proteins or other molecules in cancer cells that can provide information about an individual’s cancer. These results can help healthcare providers better understand the characteristics of the cancer and determine whether certain treatments may be appropriate.
Biomarker testing is an important part of precision medicine, an approach that uses information about a person’s cancer to help guide treatment decisions. Depending on the cancer and the biomarkers identified, testing may help determine whether a patient could benefit from a targeted therapy or certain immunotherapies. It can also provide information that may help doctors understand how a cancer is responding to treatment or whether additional testing may be appropriate if the cancer returns.
The science continues to evolve as researchers identify new biomarkers and develop better ways to detect and use them. Testing may involve a sample of tumor tissue, blood, bone marrow or another body fluid, depending on the type of cancer and the test being performed.
Not everyone needs biomarker testing, and the tests recommended depend on the type and stage of cancer, the treatment being considered, and each patient’s individual circumstances. A healthcare provider can help determine whether biomarker testing may be appropriate.