ATF4 and cancer: To elucidate how ATF4 promotes lung metastasis, we performed gene set enrichment analysis (GSEA) of the RNA‐seq data; consequently, the nuclear factor‐κB (NF‐κB) signaling pathway was determined to be significantly upregulated in cytotoxin‐induced 4TO7 NDCs (Figure 6A and Figure S4A,B, Supporting Information), which is consistent with the public microarray data from chemotherapeutic agent‐treated cancer cells (Figure 6B).