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UCSF, Mayo Team Discovers Genomic Variant That Increases Risk of Brain Tumors

By Jason Bardi    |   ucsf.edu | August 27, 2012

UCSF, Mayo Team Discovers Genomic Variant That Increases Risk of Brain Tumors

Top: An oligodendroglioma.
Botom: An IDH mutated anaplastic astrocytoma.

People who carry a "G" instead of an "A" at a specific spot in the sequence of their genetic code have roughly a six-fold higher risk of developing certain types of brain tumors, according to a study by researchers at the University of California, San Francisco and Mayo Clinic.

The study was jointly led by geneticists Margaret Wrensch, PhD, and John Wiencke, PhD, professors in the Department of Neurological Surgery at UCSF, and Robert Jenkins, MD, PhD, professor of Laboratory Medicine in the Department of Laboratory Medicine and Pathology and the Division of Laboratory Genetics at the Mayo Clinic. The findings, published in the journal Nature Genetics, could help researchers identify people at risk of developing certain subtypes of gliomas, which account for about 4,600 of the 23,000 brain cancers newly diagnosed annually in the US. This information could lead to better surveillance, diagnosis and treatment.

Based on their findings, the scientists already are starting to think about clinical tests that could tell patients with abnormal brain scans what kind of tumor they have, by simply testing their blood.

Researchers still need to understand how the specific DNA change actually causes the tumors, said Wrensch, since "this is among the first examples that a change in a non-coding portion of DNA can be so strongly associated with cancer risk."

The study began a few years ago when researchers started hunting for regions of the genome that might be associated with glioma development. They observed that a portion of chromosome eight contained single nucleotide polymorphisms, or "SNPs," that were associated with brain tumors. Then, Wrensch, Wiencke, Jenkins and their colleagues used a combination of sophisticated genomic techniques to search for the SNP that was causing brain tumors to form.

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