"Gliomas with IDH1/IDH2 mutations clearly make up a clinically and biologically distinct subgroup of brain cancers that may benefit from targeted therapies in the future," says Parsons.
IDH1, which stands for isocitrate dehydrogenase 1, was first spotted last year in results from a genomewide scan of brain cancer mutations led by the Johns Hopkins scientists. At the time, the scientists linked mutations in the IDH1 gene to roughly 12 percent of glioblastomas (or glioblastoma multiforme), the most lethal form of glioma.
Add to this the newly discovered mutations occurring in lower grade astrocytomas and oligodendrogliomas, and Parsons estimates that 6,000 adults and children with brain cancer per year in the U.S. could be affected.
"Pathologists may find it useful to determine IDH1/IDH2 status to help identify and classify these cancers," says Parsons. He added that proper diagnosis is essential because treatments differ within types of gliomas, as well as other forms of brain cancer.
"New treatments could be designed to target the enzymatic activity that is altered by these mutations," says Victor Velculescu, M.D., Ph.D., associate professor and director of cancer genetics at the Ludwig Center at Johns Hopkins.
"The mutations appear to occur very early in the progression of these cancers, perhaps at the stem cell level," adds Bert Vogelstein, M.D., Clayton Professor and co-director of the Ludwig Center at Johns Hopkins and a Howard Hughes Medical Institute investigator.
Mutations were found by a standard technique of amplifying sections of the IDH1 and IDH2 genes through polymerase chain reaction (PCR), a process that replicates bits of DNA to levels that can be detected by sensitive computer equipment.
|Contact: Vanessa Wasta|
Johns Hopkins Medical Institutions