Elusive gene mutations found for brain tumor

U.S. scientists have found two gene mutations occurring in oligodendrogliomas, the second-most common form of brain cancer, according to a study to be published Friday in journal Science. For years scientists have been looking for the primary cancer genes involved in oligodendrogliomas evolvement. Scientists know the two chromosomes held the probable mutations, but the particular gene information remains unclear. Now scientists at Duke University Medical Center and Johns Hopkins University have discovered the most likely genetic mutations that researchers have been hunting for on chromosomes 1 and 19. The genes they identified, CIC or FUBP1, are tumor suppressor genes. The cancer-related pathways that involve these genes could become targets for future treatments, said Hai Yan, a Duke associate professor of pathology and co-corresponding author of the study. The researchers found CIC on chromosome 19 and FUBP1 on chromosome 1 based on an initial study of seven oligodendrogliomas. They found six mutations and two mutations, respectively, in the seven tumors. Further study of 27 more of these tumors showed that there were 12 and three mutations of CIC and FUBP1, respectively. The two genes were rarely mutated in other types of cancers, indicating that they are oligodendroglioma-specific genes. These genes were difficult to find until the technology improved, said Yan. "The team used whole genome sequencing technology so that no genes would be excluded, and we found to our surprise that one gene, on chromosome 19, was mutated in six out of the seven initial tumor specimens we sequenced," Yan said. "A mutation frequency of 85 percent is very high." The finding of two additional new genes involved in oligodendrogliomas increases the chances for an effective combination drug therapy for the tumor, Yan said. He envisions a combination cocktail of drugs similar to the combination-drug treatments taken by HIV patients that would target different pathways involved in cancer, and assist both in reducing the chance of relapsing and increasing odds of success.