SMAD3 and cancer: EMT is a process in which cells lose their epithelial properties and gain migration and invasive ability to become mesenchymal cells, which plays an important role in cancer metastasis.49 We conducted PCR array analysis to search for EMT-related genes whose expression is correlated with ETNK2. Consequently, we found that ETNK2 mRNA expression levels positively correlated to those of AHNAK and TGFB1. Activated TGFB1 phosphorylates Smad2 and Smad3 proteins.