XBP1 and Miyoshi myopathy: Bortezomib—an effective PI utilized in certain tumours—was observed to significantly increase Xbp1 splicing across four cell types analysed: mouse bone marrow MSCs, MSCs derived from patients with MM (MM‐MSCs), MC3T3‐E1, and human MSC line immortalized by the telomerase reverse transcriptase gene expression.74, 75