MGMT and central nervous system cancer: Subsequent studies using whole-exome sequencing (WES) and immunohistochemistry (IHC) have corroborated these findings, demonstrating that up to 25–30% of recurrent MGMT-methylated gliomas acquire mutations in core MMR genes, most commonly MSH6, but also MSH2, MLH1, and PMS210,13,50–53.