IDO1 and central nervous system cancer: The expression of MAOB, IL4I1, ALDH3A2, WARS2, HAAO, AANAT, IDO1, OGDH, EHHADH, AOC1, INMT, HADHA, ALDH9A1, ALDH2, ECHS1, AADAT, ALDH1B1, CAT, HADH, GCDH, MAOA, IDO2, TPH1, and CYP1B1 was higher in glioma than normal brain tissue samples.