The Definition Of Biomarkers

A biomarker is a biological characteristic, which can be molecular, anatomic, physiologic, or biochemical. These characteristics are able to be measured and evaluated objectively and act as indicators of a normal biological or pathogenic process (a diagnostic biomarker), or a pharmacological response to therapeutic intervention (a therapeutic biomarker). A biomarker shows a specific physical trait or a measurable biologically produced change in the body connected with a disease or health condition.

The way that biomarkers are measured are by physical examination, laboratory data, or with imaging (CT, MRI, PET, x-rays). Biomarkers are found in blood and other body fluids, as well as in tissue, and show both normal conditions and the results of an abnormal disease process. Biomarkers are used to look at how well the body is responding to a treatment, since biomarkers include physical parameters which can be definitively anchored to a disease or class of diseases. In practice, biomarkers include tools and technologies that can aid in understanding the prediction, cause, diagnosis, or outcome of treatment of disease.

Diagnostic testing by the use biomarkers has been around for more than 50 years. The use of biomarkers to aid with diagnosing diseases and developing pharmaceuticals has grown widely in the 21st century. There are an abundance of biomarkers, the most important of which are currently used in developing new medications and in the areas of therapeutic medicine for diseases such as cardiovascular diseases and cancer. Biomarkers aid in the understanding of the mechanism of disease processes. Thus, the use of biomarkers plays a critical role in developing personalized medical care.

Biomarkers of exposure are used in predicting risk of disease. Biomarkers of disease are used in screening, diagnosis and monitoring of disease progression. Molecular biomarkers have the potential to identify an individual's susceptibility to disease, and can allow scientists to look at whole populations as opposed to merely relying on the family history of the disease. The ability to measure a patient's vulnerability is an extremely important method for estimating disease risk among various populations. Biomarkers show disease from its earliest manifestation to the terminal stage.

A vast number of companies are currently involved in biomarkers. These include major pharmaceutical companies and biomarker markets for a multitude of technologies and applications including the following: molecular diagnostics, drug discovery, clinical trials, and bioinformatics. The early detection of biomarkers provides a great opportunity to recognize a disease, to aid in the use of drug therapy for the patient, as well as provide information for assessing clinical outcomes of treatment.

The Food and Drug Administration has a set of criteria established for the use of biomarkers in research. The FDA has approved many medications with the aid of imaging biomarkers. For example, Betasterone, a medication used to treat multiple sclerosis, was approved based on imaging studies.

J. R. Johnson, G. Williams, R. Pazdur, “End points and United States Food and Drug Administration Approval of Oncology Drugs,” J. Clinical Oncology, 21(7), 1404-11, 1 April 2003).

http://www.biomarkers.org/index.html

http://www.fda.gov/bbs/topics/NEWS/NEW00424.html