SMAD2 and neoplasm: TGFβ is well documented as an inducer of EMT [26] and a potent stimulator of angiogenesis [27], however, neither TGFβ nor its target VEGF, which are usually elevated in tumor cells and contribute to angiogenesis and tumor metastasis [28,29], is increased in K5.Smad2-/- SCC [30].