Neural stem cells--a promising potential therapy for brain tumors.

Brain tumors can be highly aggressive and debilitating for many patients and lead to an untimely death in just a few months. Unfortunately, due to the location of many brain tumors, therapy with ionizing radiation, chemotherapeutic agents and/or surgery has limited rewards. In addition, the probability of totally removing highly infiltrative tumors, particularly gliomas, is extremely low and rarely provides a cure. The need for directed targeting and ablation of tumors with minimal damage to nearby healthy tissue has lead to the most recent findings and uses of neural stem cells for therapeutic treatment of brain tumors. Recently, some very promising studies have demonstrated that exogenous neural stem cells have the remarkable ability to migrate very long distances towards sites of metastasis after transplantation. These studies also show that intravascular injections of neural stem cells may lead to preferential migration towards central nervous system tumors. It has also been demonstrated that genetically modified neural stem cells, engineered to produce anti-tumor molecules, upon transplantation, have the ability to migrate towards tumors and reduce tumor mass directly or through a "bystander" effect. Here we review the current literature examining the promise of utilizing genetically modified neural stem cells as vehicles for CNS tumor therapy.