TGFB1 and neoplasm: The process is further driven by multiple signaling pathways—most notably TGF-β/Smad, Wnt/β-catenin, Notch, and HIF-1α—and modulated by cytokines such as IL-6, IL-8, TNF-α, HGF, and PDGF, frequently secreted by tumor-associated stromal cells [87].