Brain Cancer: New Theories and Therapies

The theory that adult stem cells in the body may trigger brain cancer growth is revolutionary, exciting—and still very much unproven. In the meantime, scientists say that genetic discoveries and other cancer research are now yielding new information that may bring new therapies.

Just two months ago, scientists working on the Cancer Genome Atlas, a project funded by the National Institutes of Health, released a genetic map of 20,000 genes in glioblastoma, the most common form of brain tumor and the kind diagnosed in Sen. Edward Kennedy. Experts say the research uncovered a dozen genetic pathways, or networks, of genes, which control the spread and growth of the tumor.

“These pathways represent targets we can attack to damage the tumor,” says Henry Friedman, M.D., co-deputy director of the Brain Tumor Center at Duke University in Durham, N.C., where Kennedy was treated. “We already have some drugs to attack some of these pathways, so this really gives us something to work with.”

One of the most exciting therapies in the pipeline involves using antibodies with isotopes that can be injected into the tumor to deliver high doses of radiation from within. The treatment is in Phase III clinical trials, Friedman says.

Joachim Baehring, M.D., director of the Yale Brain Tumor Center in New Haven, Conn., says in the past 10 years he’s seen an “explosion” in the number of experimental drugs for brain cancer, from vaccines to agents that target a tumor’s ability to grow new blood vessels. He says while the stem cell theory is only a hypothesis, it’s still useful. Although scientists haven’t yet been able to identify the genetic changes in these tumors, he says, “studying cancer cells that behave like stem cells gives us a promising focus for our genetic studies.”