Previous studies have shown that XIAP has an important role in MM cell survival by inhibiting apoptosis.31 Interestingly, in our studies XIAP expression is markedly downregulated by Len with HDACi, indicating that combination treatment not only enhances MM cytotoxicity by activating apoptotic signaling, but also inhibits anti-apoptotic protein expression. Here, XIAP is linked to Miyoshi myopathy.