Treatment with SS-b2 (40 or 80 mg/L) for 24 h caused a steady decrease in the protein expression of Bcl-2 in HepG2 liver cancer cells, whereas the expression of Bax, Cyt-c, cleaved caspase 9 and cleaved caspase 3 dramatically increased (Figures 3(e) and 3(f)). This evidence concerns the gene CASP9 and liver cancer.