Our predicted results obtained by molecular modeling suggest the binding mode of Tacotanina to the BIR3 domain of XIAP (Figure 6A,B), and are consistent with the downregulation of XIAP and subsequent enhanced levels of cleaved-Caspase-3 observed in breast cancer cells treated with Tacotanina to promote apoptosis (Figure 5). The gene discussed is XIAP; the disease is breast cancer.