EIF2AK3 and cancer: Secondly, PERK induces epithelial-to-mesenchymal transition (EMT), a significant biological process for epithelial-derived malignant tumor cells to acquire the ability to migrate, invade and form tumorsphere, by silencing E-cadherin or overexpressing Twist, which was verified to be inhibited by a small-molecule PERK inhibitor (Feng et al., 2014; Dey et al., 2015).