HGD and malignant glioma: In this study, based on the perspective of tyrosine metabolism, we found that the tyrosine metabolizing enzymes 4‐hydroxyphenylpyruvate dioxygenase (HPD), homogentisate 1,2‐dioxygenase (HGD), and fumarylacetoacetate hydrolase (FAH) were upregulated in more malignant glioma patients.