XAF1 and neoplasm: XAF1 enhances tumor cell sensitivity to various apoptotic stimuli, such as genotoxic, oxidative, and cytokine stresses and is involved in the regulation of autophagy and G2/M checkpoint of the cell cycle.15,20–22 Recently, we reported that XAF1 is activated by p53 and interferon regulatory factor (IRF)-1 and directs an apoptotic switch of p53′ cell-fate decisions function and destabilizes metallothionein 2A to drives cytotoxic metal stress response.23–25