Colorectal tumors and precursor lesions frequently display epigenetic inactivation of MGMT resulting from promoter hypermethylation, which is tightly associated with the occurrence of G:C to A:T transition mutations in the KRAS oncogene.
Then we used these assays for the analysis of MGMT and APC promoter methylation in a subset of archival formalin-fixed paraffin-embedded colorectal tumor specimens.
Recently, Herfarth et al. reported that a subset of colorectal tumors was characterized by a specific methylation pattern in the MGMT promoter associated with reduced MGMT expression.
To study the relevance of defective MGMT function by aberrant methylation in relation to the presence of p53 mutations, we studied 314 colorectal tumors for MGMT promoter hypermethylation and p53 mutational spectrum.
We conclude that a subset of colorectal tumors is characterized by a specific methylation pattern in the MGMT promoter associated with reduced MGMT expression.