The concept of biological markers in the field of risk assessment.

Abstract

Using biological markers as a means to advance toxicological science has come under increasing scrutiny. The concept of using biological fluids to identify an event affecting the organism is at least as old as associating a disease with a change in the color of the urine. What is new is the perception that rapid advances, in both conceptual understanding of toxicology and in the power of analytical biology and chemistry, greatly increase the likelihood of making advances in the development and validation of biological markers. These markers are of significance to human health and the environment, as well as to risk assessment and to other techniques applicable to regulatory decision making. Biological markers can be divided into markers of exposure, effect and susceptibility. There is a continuum between exposure and effect, with some markers being more reflective of either end of the continuum. An ideal marker is one that reflects both exposure and effect. Development of markers requires an understanding of the mechanisms by which agents enter the body, distribute, undergo metabolism and elimination, interact with target cells and molecules and produce adverse effects. The human genome project is likely to lead to a further increase in the availability of susceptible markers. There are many ethical issues concerning biological markers in general and susceptibility markers in particular. Validation of biological markers is a painstaking but necessary effort that requires a concerted effort among laboratories and research organizations.