However, a direct link of TGF-β-mediated differential activation of Erk between cancer and non-cancer cells in the same cell system has not been reported until our recent report (20), where we treated benign cells with a low concentration of TGF-β (0.1 ηg/ml), which led to Erk activation; while the treatment of the same cells with a high concentration of TGF-β (10 ηg/ml) resulted in Erk inactivation. Here, TGFB1 is linked to cancer.