TGF-β1 has been shown to increase ETS-1 expression in different types of cells including cancer cells [9] and regulation of ETS-1 activity at the post-translational levels is mediated mainly by the Ras/C-Raf/MEK/ERK1/2 pathway whose activation leads to phosphorylation of the N-terminus of the ETS-1 protein at threonine-38 and to super-activation of ETS-1 [11]. Here, MAPK3 is linked to cancer.