School of Medicine researchers have linked mutations in a gene to a benign pediatric brain tumor, a finding that will help scientists seek drug treatments that block growth of the tumors.
“Now that we understand the signature mutation in these common pediatric tumors, we can think about designing treatments that alter the pathway that gene controls,” said David H. Gutmann, M.D., Ph.D., the Donald O. Schnuck Family Professor of Neurology. “That’s important because right now we have few treatments tailored to this tumor type.”
Gutmann normally studies the tumors, known as pilocytic astrocytomas, in the context of neurofibromatosis 1 (NF1), an inherited condition that is one of the most common tumor predisposition syndromes. But pilocytic astrocytomas also occur sporadically in patients who do not have the NF1 mutation at a rate of about two to three new cases per 100,000 children per year.
To learn whether either condition could shed light on the other, Gutmann’s team performed detailed genetic and genomic analyses of tumor samples from 70 patients with sporadic pilocytic astrocytomas and nine patients with NF1. The results appeared in a recent issue of Neurology.
An early lead linking the sporadic tumors to changes in a gene called HIPK2 in a small region of chromosome 7 didn’t pan out, but it led the researchers to the nearby BRAF gene, which previously had been linked to other cancers.
“BRAF was a particularly enticing target because the signaling pathway that it controls is also controlled by neurofibromin, the protein made by the gene that is mutated in patients with NF1,” said Gutmann, director of the Washington University Neurofibromatosis Center. “This finding is exciting since a number of drugs are known to inhibit this pathway, some of which are already being tested for their ability to control the growth of other cancers.”