ERN1 and Miyoshi myopathy: This conclusion has important potential implications for the role of IRE1 in hematopoietic malignancies such as MM, because it suggests that IRE1 promotes tumor growth not only in its general role as a cytoprotective UPR mediator (Harnoss et al., 2019) but also in particular through its caspase-driven antiapoptotic LDTM product.