TGFB1 and glioblastoma: Gene set enrichment analysis based on HALLMARK signaling pathways revealed that many pathways associated with cancer development and progression, such as PI3K-AKT signaling, TGF-β signaling, Kras signaling, angiogenesis signaling, and glycolysis signaling, were aberrantly active in C1 GBM patients (Figure 3E).