STAT1 and glioblastoma: STAT1, a prototypical member of signal transducer and activator of the transcription (STAT) protein family, is downregulated under hypoxic conditions in GBM cells, while its overexpression can inhibit HIF-1α and VEGF-A expression, as well as decrease proliferation, migration, and invasion of GBM cells [79] (Table 4).