Examples for this come from the analysis of different tumor cells: Chaffer et al. demonstrated that CD44low cells (non-CSCs) can switch to a CD44high phenotype (CSCs) resulting in mammosphere formation, a phenotype that could be induced by upregulation of the zinc finger E-box binding homeobox 1 (ZEB1) protein expression induced by TGF-ß (548), which is a major cytokine of the TME (545). Here, ZEB1 is linked to neoplasm.