For the KEGG pathway analysis, DEGs that were specifically regulated in A549 parental cells were involved in cancer-related KEGG pathways such as TNF signalling pathways (CXCL1 and CREB5), ECM-receptor interaction (ITGB4 and COL5A2), Natural killer cell-mediated cytotoxicity (TNFRSF10D and ULBP1) and MicroRNAs in cancer (HMOX1, PLAU and MIR23B) (Figure 12). Here, TNF is linked to cancer.