We therefore examined the role of BIM in paclitaxel-induced cell death in a variety of experimental systems in in vitro and in vivo; bim−/− MEFs (Figure 1), the bim−/− mouse breast tumor model (Figure 2 and 3), and shRNA-mediated down-regulation of BIM in human breast cancer cells (Figure 6). The gene discussed is BCL2L11; the disease is breast cancer.