Hotspots in two areas of a gene that encodes a specific signaling enzyme, or kinase, are vulnerable to a variety of mutations found in five types of brain cancers, according to a report published in the August 1 issue of the journal Cancer Research. Mutations in the gene PIK3CA occur spontaneously as part of the brain tumor development rather than being passed genetically between generations, said Hai Yan, M.D., Ph.D., the senior scientist of the studies. ''PIK3CA mutations are known to occur in as much as 30 percent of colorectal and gastric cancers and glioblastomas and they are also present, to a lesser extent, in breast and lung cancer,'' Yan noted. ''Our studies defined the association of mutant PIK3CA gene in a wider spectrum of adult and pediatric brain tumors as well.''