PRF1 and glioblastoma: To further understand the cytotoxic function of the allogeneic CD8+ effector T-cell, we stained the T-cell in different GBM niches with T-cell activation markers CD154 and CD69, and cytotoxic function markers such as granzyme B (GZMB) and perforin (PFN) (Figure 3, Figure 3—figure supplement 1).