XBP1 and cancer: Intriguingly, the other reticular arms of the ISR such as the splicing of X-box binding protein 1 (XBP1)150, as well as the derepression of activating transcription factor 4 (ATF4) and ATF6151,152 are not mechanistically linked to the immunogenicity of dying cancer cells, meaning that solely the phosphorylation of eIF2α constitutes a pathognomonic feature of ICD149,153.