Definition:
A biological characteristic that can be normal, or can be associated with a particular disease or condition.
With cancer, the term biomarkers is most often used to describe substances in the blood that can be measured through a blood test. The level of these substances can help physicians monitor the progress of the cancer or evaluate the response of the cancer to therapy.
Examples:
PSA (prostate specific antigen) is a biomarker that is measured in the blood to screen for and monitor treatment for prostate cancer.
