Gene Network May Lead to Brain Cancer Breakthrough

TORONTO, July 14, 2009— -- In what one expert called a "fantastic breakthrough," researchers have described a network of genetic changes involved in the development and progression of fatal brain tumors.

While research interest in brain tumors has always been high, the treatment of brain cancer has been the focus of heightened media interest since Senator Ted Kennedy was diagnosed with a tumor more than a year ago.

The details of Kennedy's condition have been closely guarded, but the senator has not been present in Congress for the latest healthcare reform debate.

In the new study, researchers led by Dr. Markus Bredel of Northwestern University Feinberg School of Medicine in Chicago analyzed tissue from almost 200 tumors and identified the same pattern of mutations occurring in the same area or territories on 10 chromosomes.

By carefully tracking these so-called "landscape genes," the researchers were able to predict how long the patients would live, according Bredel's study, which was published today in the Journal of the American Medical Association.

The National Cancer Institute estimates that about 51,000 new cases of brain and central nervous system tumors are diagnosed in the United States each year. That number includes both malignant and non-malignant tumors, but the researchers in this study concentrated on glioblastoma -- a type of tumor that is uniformly fatal.

Analysis of glioblastoma in several patient populations yielded persistent patterns of genetic alteration involving so-called "territories" on 10 chromosomes, according to Bredel and his colleagues.

According to NCI statistics, brain tumors are more likely and more deadly in whites than in other races, and men have a higher brain cancer rate than women.

The finding that landscape genes appear to predict survival may also have an implication for treatment of glioblastoma, since attempts to intervene with therapies targeting single genes have not been successful.

The complexity of the landscape model "helps explain the lack of therapeutic efficacy of strategies targeting single gene products," the authors said.

Targeting Landscape Genes to Fight Brain Cancer

The study "implies that if we can attack the most important 'landscape' genes, then we should have a more guided approach to destroying the cancer," said Dr. Antonio Chiocca of the Ohio State University Medical Center in Columbus.

"The military analogy is to go after the command and control leadership centers of the opposing army instead of trying to target every single soldier and military installation," said Chiocca, who was not involved in the research. "This is a fantastic breakthrough."

Writing in an accompanying editorial, Dr. Boris Pasche of the University of Alabama at Birmingham and Dr. Richard Myers, of the HudsonAlpha Institute for Biotechnology in Huntsville, Ala. said that "the potential clinical implications of these findings are significant" and that the results "highlight a pattern of codependent genetic interactions" that will need to be taken into account when developing therapies.

They also provide "a novel prognostic tool that may guide future therapeutic interventions," they said.

This article was developed in collaboration with ABC News.