Distinctive pattern of LINE-1 methylation level in normal tissues and the association with carcinogenesis.

Genome-wide losses of DNA methylation have been regarded as a common epigenetic event in malignancies and may play crucial roles in carcinogenesis. Limited information is available on the global methylation status in normal tissues and other cancer types beyond colonic carcinoma. Here we applied the combined bisulfite restriction analysis PCR to evaluate the methylation status of LINE-1 repetitive sequences in genomic DNA derived from microdissected samples from several human normal and neoplastic tissues.