XBP1 and neoplasm: In tumor bearing mice, the ER stress markers such as p-eIF2α, CHOP, IRE1α, XBP1, ATF6, DR5, GRP78, GRP94, GADD34, and sXBP1 were found to be substantially elevated as well as correlated with increased ubiquitylated protein levels and heightened expression of E3 ligases: MAFBx, MuRF1, TRAF6.