[Tobacco and DNA methylation: the case for epigenetic alterations].

TOBACCO AND DNA METHYLATION: THE CASE FOR EPIGENETIC ALTERATIONS The mechanisms of the long-term impacts of exposure to chemical substances remain poorly understood. While genotoxic and mutagenic effects have been well characterized, epigenetic mechanisms such as DNA methylation could also account for the delayed effects of exposures. It is in the case of tobacco that the strongest arguments for a role of these mechanisms have been obtained in human populations. This text presents recent data on this issue demonstrating the plausibility of epigenetic mechanisms to explain the persistence of biological signals long after stopping exposure.