TGF-β and cancer

TGF-β signaling regulates tumorigenesis and in human cancer its signaling pathways are often modified during tumor progression. Prior to initiation and early during progression TGF-β acts upon the epithelium as a tumor suppressor, however at later stages it is often a tumor promoter. Over the years, many studies have focused on the epithelial cell autonomous role for TGF-β, however, TGF-β is not strictly limited to this compartment in vivo. Recent studies addressing TGF-β mediated stromal–epithelial interactions have significantly improved our understanding related to the regulation of cancer. In addition, stromal fibroblast cell autonomous effects have been observed in response to TGF-β stimulation. According to the current literature and experimental evidence, TGF-β is a potent ligand that regulates carcinoma initiation, progression and metastasis through a broad and complex spectrum of interdependent interactions.