ER stress and UPR play a significant role in plasma differentiation and MM.
IRE1α-XBP1 signaling pathway is an important branch of UPR.
XBP1s levels could predict the prognosis of MM.
XBP1s levels could assess the effect of thalidomide and bortezomib therapy.
Many targeted drugs develop anti-tumor effect by regulating IRE1α-XBP1 pathway.