XBP1 and familial pancreatic carcinoma: Moreover, the gene expression of many ERAD-related molecules is significantly reduced in skeletal muscle of KPC tumor-bearing Xbp1mKO mice compared with corresponding Xbp1fl/fl mice (Supplemental Fig. EV4C) suggesting that XBP1-mediated ERAD activation may also contribute to muscle proteolysis during pancreatic cancer cachexia.