XBP1 and cancer: The activation of unfolded protein response (UPR) signaling pathways, particularly the inositol-requiring enzyme 1α/x-box binding protein 1 (IRE1α/XBP1) and protein kinase r-like endoplasmic reticulum kinase/eukaryotic translation initiation factor 2 subunit α (PERK/eIF2α) pathways, has been implicated in the modulation of pain responses, suggesting that targeting these pathways could provide new therapeutic strategies for managing cancer pain [155, 156].