Interestingly, there were differences between the methylation level of the two CDH1 alleles in some non-cancerous gastric tissue samples (e.g., S12 and S14 in Figure 4), but the clear mono-allelic hypermethylation observed in the MLH1 promoter of the HNPCC patients [18-20] was not observed in the CDH1 promoter in any of the samples (Figure 3 and 4). The gene discussed is MLH1; the disease is hereditary nonpolyposis colon cancer.