CDH1 and neoplasm: Graff et al. [8] mapped the methylation patterns of E-cadherin and von Hippel-Lindau tumour suppressor genes in both normal and neoplastic cells, and found that boundaries exist between the unmethylated promoters and the nearby hypermethylated Alu elements, to maintain the unmethylated status of the promoters in normal cells, and that the boundaries may be progressively overriden by methylation of the Alu elements, resulting in promoter methylation in neoplasia.