CD274 and central nervous system cancer: (18) performed an immunohistochemical analysis of pathological sections from 54 glioma patients and defined at least 5% of cells detected by membrane staining as PD-L1 positive (without regard to staining intensity); high PD-L1 expression was related to gliomas and OS under multifactorial analysis (HR=4.958, 95% CI:1.557–15.79).