H2AX and Miyoshi myopathy: Through Western blotting, we observed that dl922-947 and AZD1775, both alone and in combination at their respective IC50 values, induced the expression of γ-H2AX, phospho-RPA32 Ser 4/Ser 8, and phospho-CHK1 Ser 345 in both MM cell lines, which is indicative of DDR activation (Figure 3).