TGFB1 and cancer: When viewed from a molecular signaling perspective, the various EMTs, whether taking place during embryogenesis or during pathogenesis such as in cancer, seem to be initiated by physiological or abnormal activation of the major developmental signaling pathways, including the Wnt, Notch, receptor tyrosine kinase (RTK), cytokine receptor-JAK–signal transducer and activator of transcription (STAT), hedgehog, hippo, nuclear receptor and transforming growth factor β (TGFβ) pathways (Figure 2 and Figure 3) [5,6].