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The new field of toxicogenomics presents a potentially powerful set of tools to better understand the health effects of exposures to toxicants in the environment. At the request of the National Institute of Environmental Health Sciences, the National Research Council assembled a committee to identify the benefits of toxicogenomics, the challenges to achieving them, and potential approaches to overcoming such challenges. The report concludes that realizing the potential of toxicogenomics to improve public health decisions will require a concerted effort to generate data, make use of existing data, and study data in new waysâ€"an effort requiring funding, interagency coordination, and data management strategies.
Despite increasing knowledge of human nutrition, the dietary contribution to cancer remains a troubling question. Carcinogens and Anticarcinogens assembles the best available information on the magnitude of potential cancer riskâ€"and potential anticarcinogenic effectâ€"from naturally occurring chemicals compared with risk from synthetic chemical constituents. The committee draws important conclusions about diet and cancer, including the carcinogenic role of excess calories and fat, the anticarcinogenic benefit of fiber and other substances, and the impact of food additive regulation. The book offers recommendations for epidemiological and diet research. Carcinogens and Anticarcinogens provides a readable overview of issues and addresses critical questions: Does diet contribute to an appreciable proportion of human cancer? Are there significant interactions between carcinogens and anticarcinogens in the diet? The volume discusses the mechanisms of carcinogenic and anticarcinogenic properties and considers whether techniques used to evaluate the carcinogenic potential of synthetics can be used with naturally occurring chemicals. The committee provides criteria for prioritizing the vast number of substances that need to be tested. Carcinogens and Anticarcinogens clarifies the issues and sets the direction for further investigations into diet and cancer. This volume will be of interest to anyone involved in food and health issues: policymakers, regulators, researchers, nutrition professionals, and health advocates.
The International Life Sciences Institute (lLSI) is a scientific foundation wh ich addresses critical health and safety issues of national and international concern. ILSI promotes international cooperation by pro viding the mechanism for scientists from government, industry and universities to work together on cooperative programs to generate and disseminate scientific data. The members and trustees of the Institute believe that questions regarding health and safety are best resolved when scientists can ex amine and discuss issues, as an independent body, se~arate from the political pressures of individual countries and the economic concerns of individual companies. Frequently, meaningful assessment of the risk of a test substance is hindered by the inherent inconsistencies in the system. The development and refinement of methods and systems to evaluate the safety of chemicals have evolved in a rapid and largely unplanned fashion. Attempts to improve the system have largely been directed toward broad general concerns, with little attention being given to specific problems or issues. A failure to resolve these problems has frequently resulted in increased testing costs and complications in the assessment and extrapolation of the results. Publicity surrounding toxicologic issues has created chronic public apprehension about the ability of science and government to deal effectively with these problems. In response to these difficulties, ILSI has assembled highly qualified and renowned scientists from research institutes, universities, government and industry, with relevant scientific knowledge and expertise regarding the issues that complicate risk assessment procedures.
Cancer has become the most critical health problem in the United States. It is expected that 25% of the people will develop this dread disease, and many of these will die from the malady. The causes of cancer are varied, but the best estimate available is that 70--90% arise from environmental factors. These statistics have triggered widespread governmental action along two lines: (l) An effort to identify those chemicals and conditions that give rise to malignant processes has been mounted by the Carcino genesis Testing Program, the National Cancer Program, and subse quently, the National Toxicology Program. (2) Regulatory laws have been enacted that are administered by agencies such as TSCA, FIFRA, EPA, FDA, OSHA, and so on, whose mission is to minimize public ex posure to carcinogens. Since direct verification that specific chemicals induce cancer in hu of unanticipated expo mans is necessarily limited to known incidences sure and is therefore rare, most chemicals are identified as carcinogens only by laboratory experiments. At present, the only accepted procedure is long-term animal bioassay, and not only are these studies expensive and time-consuming, but current worldwide resources permit the evalua tion of only 300-400 chemicals per year, a miniscule amount compared to what is available in the commercial world: 30,000 existing chemicals, with approximately 700 new such materials being introduced every year.
The varying cancer incidence from country to country and region to region suggests that en vironmental factors play a considerable role in the aetiology of cancer. Whether these factors in the environment moderate the effect of car cinogenic chemicals or whether they might them selves be carcinogenic is not known at the present time. What is known is that there are various chemicals, both naturally occurring and man-made, which can induce cancer in man. In the Western world estimates vary as to how much cancer is occupational in origin; the figures range from 1% to 40%. It is our feeling that probably about 10% of cancer has a direct oc cupational origin. Nevertheless this number is considerable and it behoves us therefore to identify those chemicals which are carcinogenic and to reduce human exposure. Recent work on the mode of action of carcinogenic chemicals suggests that the majority exert their effect through an activation step to give elec trophilic metabolites. Such metabolites have as a common feature the ability to react with cel lular nucleophiles to give covalently bound products. Such reaction will occur after carcino gen treatment of animals with nucleic acids par ticularly in target organs. It is reaction with nucleic acids that provides the basis of a num ber of short-term tests for carcinogens, since the basic composition of DNA is similar in micro-organisms and in human cells.