However, a recent study reports that the induction of ER stress in cancer cells activates the PEAK/eIF2α/ATF4 signal pathway and that GADD34 induced by severe or chronic ER stress inhibits the PEAK/eIF2α/ATF4 signal pathway via the de-phosphorylation of eIF2α [26,30]. The gene discussed is PPP1R15A; the disease is cancer.