Signals from the TGF-βs are mediated by the TGF-β receptors and their substrates, the
Smad proteins. Inactivation of either of the two transmembrane serine/threonine kinases
called the TGF-β type I and type II receptors is now known to underlie a wide variety of
human pathologies including, especially carcinogenesis. Numerous studies have now
demonstrated that the TGF-β receptor complex and its downstream signaling intermediates
constitute a tumor suppressor pathway. We review here a specific pathway of mutational …