When lung cancer cells were treated with ATO/VPA, cleaved forms of caspase-8 and caspase-9 were increased, implying that caspase-8 linked with the cell death receptor (extrinsic) pathway was activated in these cells, and caspase-9 related to the mitochondrial (intrinsic) pathway was also activated. This evidence concerns the gene CASP9 and lung carcinoma.