A recent discovery in genetics may lead to a new understanding of brain tumors and more effective methods of treatment.
A team of researchers from the Duke University Medical Center and the Johns Hopkins Kimmel Cancer Center has shown that specific types of brain tumors are often accompanied by genetic mutations in two metabolic genes.
Mutations in either one of the genes, IDH1 and IDH2, are correlated to more than 70 percent of grade II and grade III brain tumors and may be involved in the development of cancer cells.
The results of these studies suggest that these mutations lead to an entirely different type of brain tumor. This information could be useful in treating future cancer patients, said Dr. Hai Yan, the lead investigator of the study at Duke and an assistant professor of pathology.
"Although the motivation is in curing cancer, this research is scientifically fascinating," Yan said. "Brain tumors are one of the most difficult diseases to treat and this discovery may reveal the causes of brain tumors. It is impossible to devise a permanent treatment until we figure out the genetics behind it."
In patients diagnosed with glioblastoma, the most common and aggressive type of brain tumor, those with IDH1 or IDH2 mutations survived an average of 16 months longer than those without the mutations. Among patients with anoplastic astrocytomas, another type of brain tumor, those with mutated genes survived an average of 45 months longer.
Previous studies have already shown that patients with IDH1 mutations have a greater chance of survival. This newest study, published Feb. 19 in the New England Journal of Medicine, indicates that patients with IDH2 mutations do as well.
Whether this discovery will lead to an effective cancer treatment is still in question, Yan said. It is extremely difficult to perform clinical experiments because gliomas are found in the brain and experiments must be done in the developmental stages of cancer.
Yan said these mutations could also be used as markers for clinical targets or studied to discover more about the genes and their connection to brain tumors.
Because IDH1 and IDH2 are genes encoded for metabolic enzymes, there is a possible connection between metabolism and cancer, Yan said. Studies are being done to understand the chemical bonds and structural shape of the genes and their mutant proteins, along with their involvement in energy generation.
"It is a really cool discovery," said senior Marc Samsky, who worked with Yan last year. "It may not have a huge short term impact, but further research into the pathways involved in the genes and proteins can develop treatments for low grade and high grade tumors."
Samsky added that studying individual genetics may lead to cancer treatments that are more tailored to each individual patient's needs. With the capacity to distinguish individual tumors, individual treatments can be developed that could work better with different patients.
The devastating part about cancer is that it is incurable, Yan said. Although some patients are cured, the treatments are expensive and the patients never know when the cancer might come back. Targeting the genetic causes behind cancer may be its only possible cure.
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