BDKRB1 and glioblastoma: To examine the effects of B1R on immune modulation in GBM cells, the present study developed a coculture system comprising human macrophages (HMs) and B1R-OE GBM cells (hereafter referred to as HM–BIR-OE GBM system) or HMs and EV GBM cells (hereafter referred to as HM–EV GBM system).