MGMT and central nervous system cancer: Group I lines were derived from newly diagnosed, treatment-naïve, MGMT methylated, high-grade gliomas (GBM and oligodendroglioma); Group II lines were derived from newly diagnosed, treatment-naïve, unmethylated high-grade gliomas (GBM only); and Group III lines were derived from high-grade gliomas that had recurred after treatment with TMZ and RT (GBM and oligodendroglioma).