GLI1 and glioblastoma: A truncated GLI1 variant (tGLI1), detected in most GBM cases but absent in normal brain cells, promotes tumor progression by activating genes not regulated by canonical GLI1, including VEGFR1, VEGF-C, TEM7, HPSE, CD24, and CD44.297 tGLI1 drives GBM invasion by upregulating CD24 and contributes to angiogenesis through VEGF signaling.