Rag 1-/- immunodeficient mice were transplanted with U251 human glioma cells to find the most efficient glioma model for in vivo studies. In vitro studies confirmed U251 cell markers. Mice were then injected intercranially with human glioblastoma cells, and then injected intercranially with either: Neurog2, or control retrovirus. Mice were sacrificed at different time points. Tumors were examined using markers for: proliferation, vasculature, microglia, and astrocytes.