RASSF1 and neoplasm: We have shown that many tumour suppressor and tumour-related genes, such as APC, DAP-kinase, DCC, E-cadherin, hMLH1, p16, RASSF1A and RUNX3, exhibit promoter hypermethylation in both neoplastic and non-neoplastic gastric epithelia at variable frequencies (Tamura, 2004).