Application of biomarkers in cancer epidemiology. Workshop report

In epidemiology, a biological marker (commonly abbreviated, for convenience, to biomarker) is any substance, structure or process that can be measured in the human body or its products and may influence or predict the incidence or outcome of disease. Biomarkers can be broadly classified into markers of exposure, effect and susceptibility. Biomarkers may include the following: xenobiotic agents and their metabolites in tissues or body products; normally occurring body constituents whether in physiological or pathological amounts; endogenous compounds that are not present under normal conditions; and inherited and acquired abnormalities of body chemistry, structure or function, including pathological manifestations of precursors to disease. Biomarkers should be distinguished from biomarker assays, specific laboratory tests aimed at measuring particular biomarkers, and biomarker measurements, the amounts of particular biomarkers present in specified units of tissues or body products as measured by biomarker assays.