Genetic Fingerprints Reveal Origins of Brain Tumors

Genetic fingerprints reveal where a brain cell came from remain distinct even after the cell becomes a brain tumor.
The finding adds a new layer of complexity to the quest to understand the causes of childhood brain cancers, according to senior author David H. Gutmann, M.D., Ph.D., the Donald O. Schnuck family professor of neurology at the Washington University School of Medicine in St. Louis (MO, USA) and co-director of the neuro-oncology program at the Siteman Cancer Center (St Louis, MO, USA).

Our findings suggest that brain tumors arising in different regions may be genetically distinct as a consequence of their unique cellular origins, Professor Gutmann said. This is yet another factor we need to consider when trying to understand how pediatric brain tumors form. He added We were hoping to identify genes that contribute to the formation of these tumors and find indicators that might help us predict which tumors will be relatively well-behaved and which will be more aggressive.

Scientists use information about tumor origins to develop new tests and treatments for the tumors. Brain tumors are the leading cause of cancer-related death in children, and the most common childhood brain tumor is the pilocytic astrocytoma (PA). Approximately 15% of all PAs are linked to neurofibromatosis 1 (NF1), a genetic condition that causes childhood brain tumors and is a primary focus of Professor Gutmann's research. However, the genetic basis for the majority of PAs is unexplained.

Cells in different parts of the brain carry the same genes, but they also contain factors that modify the use of those genes, suppressing some genes and activating others to allow the cells to take on specialized characteristics as the brain matures. These changes in gene activity levels are called changes in gene expression. The scientists found that tumors arising in different regions of the brain retain distinct patterns of gene expression. These patterns provided genetic fingerprints or bar codes for the location of PAs, as well as for another glial cell tumor called an ependymoma. In addition, scientists also detected these distinct patterns of expression in normal glia and stem cells from these brain locations, suggesting that genetic fingerprints can be used to identify the potential origins of brain tumors.

In the new study, Professor Gutmann led six laboratories in the most detailed genetic analysis of PAs to date. A report of the study appeared in the February 1, 2007, issue of Cancer Research.


Related Links:
Washington University School of Medicine in St. Louis
Siteman Cancer Center