GENE-ENVIRONMENT INTERACTION: THE IMPORTANCE OF OMICS IN UNDERSTANDING THE EFFECT OF LOW-DOSE EXPOSURE

The risk of human exposure to environmental compounds has historically been based on the extrapolation of data from animal studies performed at high levels of exposure to single chemicals. Models used for this extrapolation include the assumption of low-dose linearity for genotoxic carcinogens and a predictable threshold for non mutagenic compounds. This concept is increasingly questioned as the theory of hormesis is more and more supported by experimental evidence. Hormesis is a term to define the biphasic dose-response to an environmental agent that can induce stimulatory or beneficial effects at low doses and inhibitory or adverse effects at high doses. The adaptative response of living organisms to the environment poses serious questions about the reliability of the current approach for risk assessment. Some other considerations should be taken in account when defining the effects of chemicals on human health. The human population is chronically exposed to low doses of environmental pollutants. Environmental and genetic factors both play a role in the development of most diseases. Environment include any external agent, which also means food and medications. The interactions among all these aspects make the comprehension of the whole picture difficult. The sequencing of the human genome has provided new tools to study the environmental impact.