Combination of Wee1 inhibitor sublethal concentration (IC20) with different doses of Chk1 inhibitor resulted in significant cell cycle arrest characterized by a decrease of the S-phase population (Supplementary Figure S4A), apoptosis potentiation (Figure 3C) and PARP1 cleavage (Supplementary Figure S4B) in MM cells compared to Chk1 or Wee1 inhibitor alone. Here, CHEK1 is linked to Miyoshi myopathy.