Blocking the activation of the IRE1α-XBP1 pathway in FKBP9-depleted GBM cells with a small molecule inhibitor could impair the effects of FKBP9 depletion on GBM cell growth, supporting a role for the UPR signaling in FKBP9-mediated activities in GBM. This evidence concerns the gene ERN1 and glioblastoma.