Briefly, GDC40 was established from a 69-year-old female patient with isocitrate dehydrogenase 1 (IDH1) wild type, O6-methylguanine-methyltransferase promoter methylation (MGMT) methylated, and telomerase reverse transcriptase (TERT) promotor mutant GBM using the neurosphere technique with the serum-free culture medium developed to isolate normal human neural stem/progenitor cells.36 The GDC519 cell line was derived from a 66-year-old male patient with the IDH1 wild type, MGMT unmethylated, and TERT promotor mutant GBM (Figure 1A). Here, MGMT is linked to glioblastoma.