STAT3 and glioblastoma: At a mechanistic level, most proposed pathways to mediate immunosuppression in GBM are those involving signal transducer and activator of transcription 3 (STAT-3) [54,55], phosphoinositide 3 kinase, Ras–mitogen-activated protein kinase, wingless-related integration site/β-catenin, and indolamine 2, 3-dioxygenase [56].