Tumour cells activate the unfolded protein response (UPR) to cope with ERS, which is controlled by three ER transmembrane sensors: inositol-requiring transmembrane kinase/endoribonuclease 1α (IRE1α), activating transcription factor 6 (ATF6), and protein kinase R–like ER kinase (PERK). This evidence concerns the gene ATF6 and neoplasm.