In preclinical models of colon cancer, PERK-inhibition made ER stress-resistant/MDR tumors as responsive to oxaliplatin as ER stress-sensitive/chemosensitive tumors: this chemosensitizing effects was likely due to the decreased expression of MRP1 that restored the pro-apoptotic effects of oxaliplatin in resistant tumors. The gene discussed is ABCC1; the disease is malignant colon neoplasm.