Disclosed is a method of treatment of an individual suffering from primary brain tumors (glioma and medulloblastoma) and brain metastases of extracranial cancers using human stem cells encoding therapeutic genes. The method includes giving the individual a clinically acceptable therapeutic reagent by intravascular injection of a pharmaceutical composition. The pharmaceutical composition includes neural stem cells (NSCs) genetically engineered to express a suicide gene (cytosine deaminase) and a cytokine gene (IFN-β) and a pharmaceutical carrier suitable for injection. The NSCs migrate selectively to tumor site in the brain, target tumor cells, kill tumor cells, inhibit tumor growth and thus treat the tumor.
