HDAC9 and Miyoshi myopathy: Many inhibitors targeting the DNA repair pathways (APEX1, PARP1, NER, HR, c-NHEJ, alt-NHEJ, ATR, MGMT, and HDAC) and cell-cycle checkpoints (CHEK1 and CHEK2) have now been developed and might be useful to induce MM cells apoptosis in combination with DNA damage-inducing drugs (Table 2).