Surprisingly, inhibition of HO activity with SnMP (10&mu;M) failed to increase BTZ sensitivity in MM cells whereas inhibition of HO-1 nuclear translocation by E64d, a cysteine protease inhibitor, increased sensitivity to BTZ and decreased genetic instability as measured by cytokinesis-block micronucleus assay. The gene discussed is HMOX1; the disease is Miyoshi myopathy.