We reported previously that NO-mediated apoptosis in human leukaemia cells is associated with mitochondrial damage (i.e., a degradation of major mitochondrial lipid cardiolipin and cytochrome c release into the cytosol) followed by an activation of caspase-9 and caspase-3 (Ushmorov et al, 1999). This evidence concerns the gene CASP9 and leukemia.