TGFB1 and neoplasm: Sorre et al. (2014) studying the influence of this cytokine on the development of Xenopus embryos showed that a pulsed stimulus is more effective than a constant elevation in TGF-β concentrations to promote signaling activation. Moreover, Nicolás and Hill (2003) analyzing the tumor suppressive role of TGF-β reported that the resistance to TGF-β-induced growth arrest exhibited by some pancreatic cancer cell lines derive from their ability to rapidly export R-SMADs to cytoplasm, while counterparts sensitive to TGF-β retain nuclear SMADs for longer periods.