Two conditions would have to be met for TRAIL to be clinically effective for treating malignant glioma: (a) a route of administration must be used that delivers concentrations of TRAIL that are lethal to the patient's glioma cells in vivo and (b) the glioma cells must be markedly more sensitive to TRAIL than normal cells exposed via that mode of delivery. The gene discussed is TNFSF10; the disease is glioma.