CD274 and brain stem glioma: More than a half of the brainstem gliomas (37 out of 62 cases) expressed varying amounts of PD-L1 (Figure 2E); 11 cases showed staining in less than 25% of the tissue, 13 showed staining in 25 to 50% of the tissue, and 13 showed staining in greater than 50% of the tissue (Figure 2E).