There are many features by which gliomas can be classified, but some of the main ones are considered to be classified by grade of malignancy (Grade I–IV) and by the presence of a mutation in the IDH1 gene (IDH1− and IDH1+), where IDH1− is also called “wild type” and IDH1+ is called “mutant type”. This evidence concerns the gene IDH1 and central nervous system cancer.