The promise of molecular epidemiology in defining the association between radiation and cancer.
Molecular epidemiology involves the inclusion in epidemiologic studies of biologic measurements made at a genetic and molecular level and aims to improve the current knowledge of disease etiology and risk. One of the goals of molecular epidemiology studies of cancer is to determine the role of environmental and genetic factors in initiation and progression of malignancies and to use this knowledge to develop preventive strategies. This approach promises extraordinary opportunities for revolutionizing the practice of medicine and reducing risk. However, this will be accompanied by the need to address and resolve many challenges, such as ensuring the appropriate interpretation of molecular testing and resolving associated ethical, legal, and social issues. Traditional epidemiologic approaches determined that exposure to ionizing radiation poses significantly increased risk of leukemia and several other types of cancer. Such studies provided the basis for setting exposure standards to protect the public and the workforce from potentially adverse effects of ionizing radiation. These standards were set by using modeling approaches to extrapolate from the biological effects observed in high-dose radiation studies to predicted, but mostly unmeasurable, effects at low radiation doses. It is anticipated that the addition of the molecular parameters to the population-based studies will help identify the genes and pathways characteristic of cancers due to radiation exposure of individuals, as well as identify susceptible or resistant subpopulations. In turn, the information about the molecular mechanisms should aid to improve risk assessment. While studies on radiogenic cancers are currently limited to only a few candidate genes, the exponential growth of scientific knowledge and technology promises expansion of knowledge about identity of participating genes and pathways in the future. This article is meant to provide an introductory overview of recent advances in understanding of carcinogenesis at the molecular level, with an emphasis of the aspects that may be of use in establishing the association between radiation and cancer.
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Office of International Health Programs, U.S. Department of Energy, Germantown, MD 20874, USA. ruth.neta@eh.doe.gov
D002453:Cell Cycle / Q000502:physiology; D004260:DNA Repair; D004777:Environment; D004812:Epidemiologic Methods; D015870:Gene Expression; D005796:Genes / Q000502:physiology; D017408:Guidelines as Topic; D006801:Humans; D008967:Molecular Biology / Q000379:methods*; D009381:Neoplasms, Radiation-Induced / Q000235:genetics*; D011110:Polymorphism, Genetic; D018570:Risk Assessment