Researchers take a major step in reclassifying brain tumors with precision

By Judy Fortin | June 11, 2015

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Daniel J. Brat

A ground-breaking study that is part of The Cancer Genome Atlas Research Network will change the way patients with diffuse gliomas, a form of brain tumor, will be diagnosed and treated in the future. More than 300 researchers from 44 institutions contributed to a molecular analysis of the tumors. They found that molecular diagnostics are much more precise and reproducible than looking at tissue under a microscope for classification.

This is a major step in starting to classify and treat brain tumors based on their genetic makeup rather than their microscopic appearance, which has been the traditional diagnostic approach for over 100 years. The findings will be published online in the New England Journal of Medicine.

Lead study author, Daniel J. Brat, MD, PhD, a researcher and neuropathologist at Winship Cancer Institute of Emory University, explains, "the use of the biomarkers in the diagnosis of these forms of brain tumors will lead to a much more consistent manner of diagnosis and patient management. It will also allow us to investigate these tumors as unified groups in a way that should advance our understanding."

The researchers studied a group of six related brain tumors, referred to as the lower grade gliomas, which have been surrounded by diagnostic confusion for decades. They used a large number of advanced molecular platforms capable of examining the genetic make-up of brain tumors (e.g. mutations, gene deletions and other genetic changes) and were able to determine that there were three well-defined tumor types based on this molecular analysis, rather than the six that had been described under the microscope.

"This is important because the classification and grade that is given with these molecular tests will be more predictive of the tumor's behavior and we'll know whether a patient's disease requires more aggressive therapy or is sensitive to specific chemotherapies," says Brat, who also is professor of pathology and laboratory medicine in Emory University School of Medicine.

About 10,000 cases of diffuse gliomas are diagnosed every year in the United States.