Analysis of DNA methylation in traditional serrated adenomas

We aimed to identify epigenetic alterations associated with the development of traditional serrated adenomas (TSAs). Through DNA methylation analysis with HumanMethylation450 BeadChip in TSAs and sessile serrated adenoma/polyp (SSA/Ps), we identified DNA methylation specifically associated with TSA development. We compared the methylation status between the protruding and flat components of the TSAs, and identified a series of CpG sites which were highly methylated in the protruding portions. We then compared the methylation status of the selected CpG sites between the protruding TSAs and SSA/Ps, and identified a set of CpG sites that were predominantly methylated in protruding TSAs.