Using neural stem cells to hunt down and kill cancer cells, researchers have successfully tested a new treatment for brain cancer. They now hope the technique will lead to an effective treatment for glioma, the most aggressive form of primary brain tumor in humans. As the Cedars-Sianai researchers note, the prognosis has historically been extremely poor for patients diagnosed with malignant gliomas. The tumors have poorly defined margins, and glioma cells often spread deep into healthy brain tissue making their surgical removal difficult. Often, pockets of tumor cells break off from the main tumor and migrate deep into non-tumorous areas of the brain. Therefore, even if the original tumor is completely removed or destroyed, the risk of recurrence is high as cells in these distant “satellites” multiply and eventually re-form a new brain tumor. Due to these characteristics, treating brain cancer has been extremely difficult.