PDCD1 and glioblastoma: Interestingly, it was reported that miR-138 can educate CD4+ T cells by down-regulating two immune checkpoints, programmed cell death 1 (PD-1) and cytotoxic T-lymphocyte-associated molecule 4 (CTLA-4), which resulted in 43% increase of survival rates in GBM mice models [22].