TGF-β family signaling in stem cells

► Normal and cancer stem cell properties are defined by their microenvironments. ► TGF-β family proteins play key roles in stem cell maintenance and differentiation. ► TGF-β family proteins mediate communication between stem cells and niche. ► TGF-β signaling mediates epithelial-mesenchymal transition in cancer stem cells. ► TGF-β family proteins regulate embryonic stem cell self-renewal and differentiation.