The finding adds new understanding about the causes of childhood brain cancers, according to senior author David Gutmann, co-director of the neuro-oncology program at the Siteman Cancer Center.
“Our findings suggest that brain tumors arising in different regions may be genetically distinct as a consequence of their unique cellular origins,” Gutmann said. “This is yet another factor we need to consider when trying to understand how pediatric brain tumors form.”
Researchers use information about tumor origins to develop new 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).
In the new study, Gutmann led detailed genetic analysis of PAs. Previous studies have failed to produce any solid leads on the genetic alterations that predispose children to PAs.
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 researchers found that tumors arising in different regions of the brain retain distinct patterns of gene expression. These patterns provided genetic fingerprints 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.
“We won’t fully understand the causes of pediatric brain tumors until we consider them in the context of factors that shape the development and specialization of different brain regions,” concluded Gutmann.