TGFB1 and neoplasm: Indeed, different from the stage of tumor onset, in the later stage of neoplastic progression, TGF-β orchestrates CSCs’ metastatic spread through the activation of Smad proteins, which in turn regulate the expression of target genes, such as master transcription factors Snail, Zeb1, Zeb2 and Twist, that drive the EMT program [133,134,135].