A biomarker, or biological marker, is a measurable indicator of a biological state or condition. Biomarkers can have molecular, histologic, radiographic, or physiological characteristics. Examples of biomarkers include everything from blood pressure and heart rate to MRI findings to complex histologic and genetic tests in blood, other body fluids, or tissues that serves as an indicator of a particular physiological state. A biomarker’s detection may be a sign of a normal or abnormal process, or of a condition or disease. There are different types of biomarkers including diagnostic which determine the presence and type of disease, prognostic which give information on the patient’s overall disease outcome with or without standard treatment, or predictive which help to identify which treatment the patient is most likely to respond to or benefit from.
Biomarkers are unique for each person and disease and can give personalized insight into treatment options. A genetic test (in some cases biopsy) is necessary to obtain this crucial information.