DNA methylation can also affect the sensitivity to targeted therapy drugs by altering DNA repair related genes.685 For example, O-6-methylguanine-DNA methyltransferase (MGMT) is a key DNA damage repair gene, and low methylation of the MGMT promoter leads to reduced sensitivity to TMZ in GBM.686 Additionally, DNA methylation can impact the transport of targeted drugs into cells, thereby affecting drug sensitivity. This evidence concerns the gene MGMT and glioblastoma.