In this respect, the new classification system, merging classical histologic classification and molecular genetic data alterations, divided GBMs into primary GBMs (IDH (Isocitrate dehydrogenase) wild-type) and secondary GBMs (IDH mutant) (10–12), allowing as well a better characterization of gliomas (20, 21). The gene discussed is IDH2; the disease is central nervous system cancer.