IDO1 and central nervous system cancer: B and T lymphocyte attenuator (BTLA), CD200 receptor 1 (CD200R1), PD-L1, B7 homolog 3 (B7-H3), CD70, cytotoxic T lymphocyte-associated protein 4 (CTLA4), indoleamine-pyrrole 2,3-dioxygenase 1 (IDO1), and PD1 (Diesendruck and Benhar, 2017) expression were significantly upregulated (p < 0.0001) in the CDC42 high expression glioma patients (Figures 8A, B).