CASP9 and hepatocellular carcinoma: As shown in Figure 2A and 2B, and 2C, the higher dose of ABT-263 (10–20 μM) treatment for 24 h induced significant DNA fragmentation and caspase 9 or 3 cleavage activation in HCC cells, whereas lower concentrations of ABT-263 (0–2.5 μM) had no apoptotic toxicity to HCC cells.