Report - Many cancers linked to environmental factors
In a report published this month, The Association for Research and Treatments Against Cancer (ARTAC) states that the majority of cancers may be linked to factors external to the body.
The report, ‘Basic properties and molecular mechanisms of exogenous chemical carcinogens’ was published in the American Journal Carcinogenesis in November. The authors, Philippe Irigaray and Dominique Belpomme, found that most cancers are exogenous, caused by external factors, rather than endogenous, caused by internal factors.
Until now, chemical carcinogenesis has predominantly been attributed to endogenous factors. However, this report highlights that exogenous chemical carcinogens (ECCs), which result from tobacco smoking or from involuntary exposure to environmental chemicals may also be important contributors to carcinogenesis. It is already known that this is the case for micro-organisms and ionizing radiation.
Exogenous chemical carcinogenesis is an extremely complex multi-factorial process during which gene-environment interactions, involving chronic exposure to ECCs and polymorphisms of cancer susceptibility genes, add further complexity.
The report describes the properties and molecular mechanisms of ECCs that contribute to induce and generate cancer, and discusses the hypothesis according to which these properties and mechanisms may make exogenous chemicals more prone to cause cancer than endogenous natural molecules. ECCs have different characteristics – but most share the basic ability to build-up in the body, to bio-accumulate, and from here they may be released into the blood circulation and target peripheral tissues for carcinogenesis. Another basic property of ECCs is their ability to induce stable and bulky DNA adducts which cannot be simply repaired by the different repair systems and so generate mutations. In addition, following ECC exposure, mutations of genes may also be caused indirectly by free radical production and by epigenetic alterations.
The report concludes that because of the numerous and complex molecular properties and action mechanisms, ECCs could be major contributors to human cancer, and therefore are a clear threat to public health.
Last updated on 10 June 2011