CASP9 and breast cancer: Immunohistochemistry demonstrated much higher expression of the active forms of caspase-3 and caspase-9 in mammary tumors of mice treated with α-mangostin (Figures 6D, F) when compared to those of the control animals (Figures 6C, Figure 6E), suggesting that α-mangostin induces mitochondria-mediated apoptosis in mammary tumor cells in vivo as well as in vitro.