OBJECTIVE: To investigate the expression of SMAD proteins in human thyroid tissues since the inactivation of TGF-?/activin signaling components is reported in several types of cancer. Phosphorylated SMAD 2 and SMAD3 (pSMAD2/3) associated with the SMAD4 induce the signal transduction generated by TGF-? and activin, while SMAD7 inhibits this intracellular signaling. Although TGF-? and activin exert antiproliferative roles in thyroid follicular cells, thyroid tumors express high levels of these proteins. MATERIALS AND METHODS: The protein expression of SMADs was evaluated […]