A 2013 study by Liu et al. [50] found that the upregulation of PD-L1 by neurons in the brain tissue adjacent to the tumor is positively associated with survival in GBM, while the lack of neuronal PD-L1 expression was linked to a high PD-L1 expression in tumor cells and an unfavorable prognosis. The gene discussed is CD274; the disease is neoplasm.