Figure 3.

Schematic of the consequences of attempted mismatch repair over an unrepaired alkylated residue in an MGMT-deficient background. Alkylation of DNA in the absence of MGMT function will result in transition mutations, regardless of mismatch repair proficiency. These lesions, in the presence of proficient mismatch repair, will give rise to futile MMR cycles, resulting in the generation of DSBs in DNA. These DSBs may potentially induce various sorts of chromosomal aberrations, including aneuploidy, loss of heterozygosity, and chromosomal translocations.