Our data revealed that CaM antagonists induced the activation of caspase-8 and caspase-7 in U266 and MM1.S cells but not in RPMI 8226 cells and the activation of caspase-9 and caspase-3 in all MM cell lines, suggesting that CaM antagonists induced apoptosis via the extrinsic pathway in U266 and MM.S cells and via the intrinsic pathway in all cell lines. Here, CASP8 is linked to Miyoshi myopathy.