A known hallmark of late-stage apoptosis is the caspase-3-dependent cleavage of genomic DNA into ~180 bp fragments and multimers thereof, which can be detected via agarose gel electrophoresis and appear as ‘laddering’.24,25 To further examine the potential role of caspases in NaD1-mediated cytotoxicity and whether NaD1 induces DNA fragmentation in tumor cells, the DNA fragmentation assay was performed at 6, 16 and 24 h after NaD1 treatment. This evidence concerns the gene MT-ND1 and neoplasm.