ARF1 and neoplasm: In the previous study, we demonstrated that selective deletion of Arf1 in cancer stem cells induces anti‐tumor immunity and an inflammasome‐mediated cancer cell necrosis/pyroptosis,[27] we analyzed cell death in the co‐culture model of Arf1‐ablated tumor cells and DCs (Figure S1b, Supporting Information) and found no significant difference in dying cells between the Arf1‐ablated and control tumor cells (Figure S2a,b, Supporting Information), suggesting that the cancer cell necrosis depends on T cells rather than DCs.