While one previous study [18] detected MLH1 methylation in 10/18 (56 %) of LS-adenomas by methylation-specific PCR, which is not a quantitative method, our frequency (1/30, 3 %, for region C methylation in adenomas with silenced MLH1 protein) complies with other quantitative studies for the same region suggesting that in a small but definite proportion (2–15 %) of tumors from LS patients the wild-type allele is inactivated by MLH1 promoter hypermethylation [19–22]. This evidence concerns the gene MLH1 and adenoma.