The trick remains preventing recurrence.

• Position: Brain Tumors - Brief article

Like normal stem cells, cancer stem cells have the ability to self-renew and generate new cells but, instead of producing healthy cells, they create cancer cells. In theory, if the cancer stem cells can be destroyed, a tumor may not be able to sustain itself, but if the cancer originators are not removed or destroyed, a tumor will continue to return despite the use of existing cancer-killing therapies.

Researchers at Cedars-Sinai Neurosurgical Institute, Los Angeles, Calif., identified certain fragments of a protein (CD133) that is found on cancer stem cells of some brain tumors and other cancers. In the laboratory, they cultured the proteins with dendritic cells, the immune system's most powerful antigen-presenting cells, which are responsible for helping the immune system recognize and attack invaders.

Studies showed that the resulting vaccine was able to stimulate an immune response against the CD133 proteins without causing side effects such as an autoimmune reaction against normal cells or organs.

"CD133 is one...