Intracranial implantation of control cells, cells with individual knockout of HIF1α or HIF2α, and cells with simultaneous knockout of HIF1α and HIF2α, followed by intraperitoneal injection and continuous TMZ treatment (2 mg/kg) for 3 weeks, revealed reduced tumor volume and weight, as well as prolonged median survival time in the individual knockout groups (Con vs. HIF1α-ko vs. HIF2α-ko = 27 days vs. 27 days vs. 29 days). This evidence concerns the gene HIF1A and neoplasm.