DNA methylation is one of the most important part in epigenetic modifications,and aberrant gene methylation plays a critical role in tumorigenesis.Many studies have indicated that DNA methylation is related to single nucleotide polymorphism(SNP) which may modify the methylation sites or influence the biological function of enzymes related to DNA methylation,change the status of genes' methylation,wihch in turn,contribute to tumorigenesis.The role of epigenetic(such as DNA mehtylation) and mutation(such as S...