XIAP and cancer: Our data demonstrate that B5 induced the activation of caspases 3, 8, and 9 in CaSki and SiHa cells (Fig. 2C) and downregulated the expression of XIAP (Fig. 2C), indicating that B5 induced apoptosis in cancer cells through the intrinsic as well as extrinsic apoptotic pathways as evidenced by the activation of caspase 8 [43].