ERN1 and cancer: The high levels of activation and expression of the three major branches of ER markers (IRE1, PERK, and ATF6) and the associated molecular chaperone GRP78 have been reported in numerous human cancers (lymphoma and myeloma) and solid tumors (breast, gastric, lung, liver, esophageal, and colon cancers) in multiple studies [11,12,13].