Search

Background: Development of graphical/visual presentations of cancer etiology caused by environmental stressors is a process that requires combining the complex biological interactions between xenobiotics in living and occupational environment with genes (gene-environment interaction) and genomic and non-genomic based disease specific mechanisms in living organisms. Traditionally, presentation of causal relationships includes the statistical association between exposure to one xenobiotic and the disease corrected for the effect of potential confounders., Methods: Within the FP6 project HENVINET, we aimed at considering together all known agents and mechanisms involved in development of selected cancer types. Selection of cancer types for causal diagrams was based on the corpus of available data and reported relative risk (RR). In constructing causal diagrams the complexity of the interactions between xenobiotics was considered a priority in the interpretation of cancer risk. Additionally, gene-environment interactions were incorporated such as polymorphisms in genes for repair and for phase I and II enzymes involved in metabolism of xenobiotics and their elimination. Information on possible age or gender susceptibility is also included. Diagrams are user friendly thanks to multistep access to information packages and the possibility of referring to related literature and a glossary of terms. Diagrams cover both chemical and physical agents (ionizing and non-ionizing radiation) and provide basic information on the strength of the association between type of exposure and cancer risk reported by human studies and supported by mechanistic studies. Causal diagrams developed within HENVINET project represent a valuable source of information for professionals working in the field of environmental health and epidemiology, and as educational material for students., Introduction: Cancer risk results from a complex interaction of environmental exposures with inherited gene polymorphisms, genetic burden collected during development and non genomic capacity of response to environmental insults. In order to adopt effective preventive measures and the associated regulatory actions, a comprehensive investigation of cancer etiology is crucial. Variations and fluctuations of cancer incidence in human populations do not necessarily reflect environmental pollution policies or population distribution of polymorphisms of genes known to be associated with increased cancer risk. Tools which may be used in such a comprehensive research, including molecular biology applied to field studies, require a methodological shift from the reductionism that has been used until recently as a basic axiom in interpretation of data. The complexity of the interactions between cells, genes and the environment, i.e. the resonance of the living matter with the environment, can be synthesized by systems biology. Within the HENVINET project such philosophy was followed in order to develop interactive causal diagrams for the investigation of cancers with possible etiology in environmental exposure., Results: Causal diagrams represent integrated knowledge and seed tool for their future development and development of similar diagrams for other environmentally related diseases such as asthma or sterility. In this paper development and application of causal diagrams for cancer are presented and discussed.

Chemoprevention is in an area of cancer research with perhaps the greatest potential for reducing cancer mortality. Several agents, and in particular antioxidant vitamins, appear to be effective against early rather than later steps of the premalignant process at different sites. Particular attention must be paid to possible side effects and safety of the agents and to optimal doses in long-term administration regimens. The results of numerous trials on the preventive role of vitamins (e.g. beta-carotene, retinols, retinoids, alpha-tocopherol, ascorbic acid, folic acid) are contradictory and far from conclusive. Multiple primary and secondary intervention trials currently under way should assess in the coming years the role of some vitamins in the prevention of various cancers (oral cavity, pharynx, oesophagus, colon, lung, breast, skin, cervix, bladder).

A descriptive study aimed at comparing mortality and dietary patterns in Italy and the Czech Republic was conducted in the period 1970-1990. Mortality from all causes, all cancers, selected site specific cancers and cardiovascular diseases were found to be generally higher in the Czech Republic than in Italy. The North-South gradients observed within Italy have diminished in the course of the last twenty years, mostly due to a less contained decrease of the mortality from cardiovascular diseases and to a marked increase in cancer mortality for Southern regions compared to Central and Northern regions. The mediterranean diet with many health promoting, possibly protective components, mostly of vegetable origin, is consumed in most parts of Italy, particularly in the South. In contrast, a Central European diet abounding in animal products and lacking in fresh fruit and vegetables is generally followed in the Czech Republic. These differences in diet may play a role in the origin of the observed differences in mortality patterns. Some factors other than diet, such as smoking habits, alcohol consumption, endogenous factors, and occupation, that are not considered here, are known to be involved in the causation of some types of cancer. The results of this study are compatible with the hypothesis of a relevant role played by dietary and other life-style habits in the etiopathogenesis of neoplastic and cardiovascular diseases.