Transforming Growth Factor-ß: An Agent of Change in the Tumor Microenvironment.

Transforming Growth Factor-ß (TGF-ß) is a key regulator of embryonic development, adult tissue homeostasis, and lesion repair. In tumors, TGF-ß is a potent inhibitor of early stage tumorigenesis and promotes late stage tumor progression and metastasis. Here, we review the roles of TGF-ß as well as components of its signaling pathways in tumorigenesis. We will discuss how a core property of TGF-ß, namely its ability to change cell differentiation, leads to the transition of epithelial cells, endothelial cells and fibroblasts to a myofibroblastoid phenotype, changes differentiation and polarization of immune cells, and induces metabolic reprogramming of cells, all of which contribute to the progression of epithelial tumors.