ZEB1 and cancer: Although the hypothesis proposed by Gupta et al. seems to oppose the current view on the tumor-suppressive functions of SLUG in melanoma, their observations do not contradict the plasticity model described by Caramel et al.: the differentiation factor SLUG can allow reversion of the ZEB1/TWIST-driven invasive phenotype toward a differentiated phenotype that enables outgrowth of disseminated cancer cells similar to a mesenchymal-to-epithelial transition (MET) in carcinomas.