Previous studies have demonstrated that the PERK specific inhibitor GSK2656157 reduces cancer cell growth in vivo by impairing angiogenesis and reducing amino acid metabolism.57 However, administration of GSK2656157 to mice for 2 weeks caused pancreatic degeneration and other long-term toxicities.57, 58 By contrast, ISIRB is well-tolerated and restores protein synthesis without causing pancreas toxicity.59 Our study is in agreement with these observations since ISRIB did not impact the normal pancreatic parenchyma adjacent to the orthotopic tumors. This evidence concerns the gene EIF2AK3 and cancer.