MRC1 and hyperinsulinemic hypoglycemia, familial, 4: In summary, SBS11 is observed in TMZ-treated cells, where MMR is either deficient or overwhelmed by the large numbers of O6-meG adducts mispairing with T. This signature is expected to be also observed in tumors, which acquired TMZ-resistance due to the mechanisms other than the MMR deficiency if they were exposed to high TMZ concentrations and the MMR capacity was exceeded.