TGFB1 and cancer: In addition to the “intrinsic” regulation of EMT-TFs in cancer cells, various extracellular signals and intracellular pathways associated with an aggressive tumor microenvironment (TME) modulate EMT either directly or indirectly, including the cytokine transforming growth factor-β (TGFβ), tumor necrosis factor-α (TNFα), Notch, JAK/STAT, Wnt/β-Catenin, and PI3K/Akt/mTOR [14,15,16,17,18].