ABSTRACT
The majority of cancers have a complex etiology. Usually one or more environmental risk
factors, such as lifestyle, diet, chemical pollutants, radiation, and infectious agents, are
implicated. Individual response to these factors is influenced by genetic background,
co-exposures to environmental agents, and other factors including age, sex, and socio-
demographic status. Despite the acknowledged importance of the environment in
influencing cancer risk, the precise contribution of individual factors and their interaction,
both with each other and with genotype, is difficult to elucidate. This is partially due to
the challenges inherent in accurately measuring exposure, not least when the critical
period relevant to disease risk may have occurred many years prior to diagnosis (1). It is
in response to this need that one of the promises of molecular cancer epidemiology is to
provide biomarkers that will refine exposure assessment (2). While the focus of this
chapter is on biomarkers, it is important to note that other approaches to refining exposure
assessment are also important, including geographic information systems, personal and
environmental monitoring, and increasingly sophisticated questionnaires (3,4); it is a
combination of tools which is most likely to provide the answers required.
