The peptide concentration in this experiment was chosen based on a previous report, which showed that 5 μM TL had limited (about 20%) toxicity to lymphoma cells (U937) and that lower concentrations (2.5 μM) of TL showed little effect on the viability of other human cancer cell lines (Hut-78 and K-562).16c We found that the fluorescence intensity of CF increased within a few minutes after the addition of caspase-3 (1 U μL–1), which indicated the release of CF from the liposomes. This evidence concerns the gene CASP3 and cancer.