To further determine survivin inhibition plays a critical role in sensitizing ABT-263 to induce apoptosis in HCC cells, we down-regulated survivin expression in HCC cells by siRNA duplexes targeted against human survivin mRNA, and then examined the expression of survivin by Western blotting (Figure 4C) and apoptotic events after ABT-263 treatments. The gene discussed is BIRC5; the disease is hepatocellular carcinoma.