the Influence of Oxidative Stress, Carcinogens and Cloning on DNA Methylation

DNA methylation is an epigenetic modification established during embryogenesis and reset during development. It is an essential process for cell differentiation, gene expression control, regulation of vital cell functions and successful mammalian development. Aberrant DNA methylation patterns have frequently been associated with carcinogenesis, with a general loss of genomic 5-methylcytosine and a hypermethylation of particular genes. Therefore, the analysis of the genomic methylation level would provide a comprehensive tool for the correlation between 5-meC-mediated biological variations and cancer development as well as other cell abnormalities. DNA adducts (another chemical modification of DNA formed via attack of exogenous or endogenous chemical reactive agents) have frequently been found to be the first step in the development of a cancerous cell and to contribute to tumour aetiology. Thus the analysis of DNA modifications is of great importance, as these represent valuable biomarkers for exposure to pollutants and carcinogens as well as reflectors of the risk of cancer formation or other aging disease