CD274 and glioma: In primary gliomas, expression of PD-1 and PD-L1 was found in 9 (22.0%) and 14 (33.3%) patients, respectively; in contrast, 25 (61.0%) and 31 (74.0%) of the lesions, respectively, had positive PD-1 and PD-L1 expression in their corresponding recurrent gliomas.