Our results therefore suggest that the oncoprotein p27 reorganizes the effects of TGF-β in thyroid cancer, explaining the slow proliferation but lack of apoptosis and metastatic behavior of PTC.
Thyroid cancer cell lines and tissues with high levels of Skp2 protein presented high p27 degradation activity and there was an inverse correlation between Skp2 and p27 expression in thyroid cancer tissues (n=68; P<0.05).
In summary, our results indicate that constitutive signalling of the MAP kinase cascade contributes to the development of thyroid cancer promoted by activated RAS and BRAF oncogenes and that this occurs, at least in part, by compromising the inhibitory function of p27.