Subcutaneous xenograft assays showed that AIF knockout reduced the growth rate of ESCC xenografts (Figure S4C, Supporting Information), which is consistent with the findings of a recent study that revealed the role of AIF in the maintenance of cancer cell survival.[22] Moreover, ectopic expression of AIFWT or AIFK255R completely reversed the growth‐suppressive effect, while expression of AIFK244R did not reverse this effect (Figure S4C, Supporting Information), suggesting that K244 was essential for the prosurvival role of AIF in cancer cells. This evidence concerns the gene AIFM1 and cancer.