We found that 15 of the MSI-positive tumours had hypermethylation of either p16, BRCA1 or RASSF1A gene, whereas none of the MSI-negative tumours (MSS) demonstrated the promoter hypermethylation and this could be due to the epigenetic inactivation of either p16, BRCA1 or RASSF1A genes (unpublished data). This evidence concerns the gene RASSF1 and neoplasm.