Despite IFN-γ, GM-CSF, IL-1β, IL-4, IL-6, IL-10, and TGFβ1 failing to directly induce breast cancer cell death in combination with an IAP antagonist (Supplementary Figure 1), it is possible that these cytokines stimulate the production of TNFα by macrophages and T cells to indirectly mediate breast cancer cell death when an IAP antagonist is given. Here, IL6 is linked to breast cancer.