Smad-Signaling in Mammary Gland Development and Tumorigenesis

The Transforming Growth Factor-β (TGFβ) superfamily of cytokines regulates a myriad of cellular processes including proliferation, differentiation and tumorigenesis. Signaling by these growth regulatory molecules is propagated by ligand-induced heterooligomerization of distinct type II and type I serine/threonine kinase receptors, which result in activation of receptor-activated Smad proteins as well as Smad-independent pathways. Disruption of TGFβ induced signaling can contribute to development and progression of human breast cancer. The role of Smad-signaling in mammary gland development and tumorigenesis will be the focus of this review.