ABSTRACT
The field of epidemiology has dramatically changed, as a result, is poised to make new major contributions to our understanding of cancer etiology, risk assessment and prevention. This chapter provides an overview of the opportunities offered by the use of biomarkers in cancer epidemiology and risk assessment, as well as summarizes the main categories of biomarkers and the issues related to their application. At the least, the use of biomarkers can provide independent confirmation of results obtained with exposure information collected through questionnaire or external monitoring. Thus, molecular epidemiology has the potential for contributing greatly to our further understanding of cancer biology, as well as to early detection and risk assessment. A biomarker is considered valid if it measures well what it is supposed to measure. When the inter- vs. intraindividual variability of a biomarker has been described, additional investigations need to be conducted to characterize the main sources for this variability.
