The authors were able to modify the mesenchymal stem cells to release exosomes containing miR-199a, which is known for preventing the development of adult glioma by down-regulating Arf GTPase-activating protein (ArfGAP) with ArfGAP with GTPase domain, ankyrin repeat and PH Domain 2 (AGAP2) MiR-199a was poorly expressed in the glioma tissues and cells while AGAP2 was found to be highly expressed, suggesting that mesenchymal stem cells successfully delivered miR-199a to the tumor cells via the released exosomes, resulting in suppression of glioma cells in adults. The gene discussed is AGAP2; the disease is glioma.