As shown in Figure 1G,H, HPD, HGD, and FAH were able to clearly distinguish glioma patients with different characteristics (including WHO grade, IDH mutation status, and 1p/19q codeletion status) in two patient cohorts, suggesting that the expression level of tyrosine metabolizing enzymes could be used as a criterion to classify the malignant degree of glioma. This evidence concerns the gene IDH1 and glioma.