ZEB1 and neoplasm: EMT is a reversible process that is driven by tumour-intrinsic as well as tumour-extrinsic mechanisms mediated by growth factors, including transforming growth factor beta (TGF-β) and epidermal growth factor (EGF), by EMT-inducing transcription factors such as Snail, Twist, Slug, ZEB1 and FOXC2, and by the suppression of microRNAs (miRNAs) such as miR-200 and miR155 [39–45].