Many studies suggest that EMT occurring in metastasizing cancer cells is induced by microenvironmental factors such as TGF-β, leading to reversible changes in master regulators of the EMT program, such as transcription factors Twist and Snail, or epigenetic modulation by changes in microRNA expression of the mir200 family, rather than by permanent genetic changes [50,51]. This evidence concerns the gene TWIST1 and cancer.