TP53 and nicotine dependence: There were 16 down-regulated pathways: nicotine addiction, P53 signaling pathway, ferroptosis, endometrial cancer, oxidative phosphorylation, cysteine and methionine metabolism, alpha-linolenic acid metabolism, amino sugar and nucleotide sugar metabolism, pancreatic cancer, chronic myeloid leukemia, carbon metabolism, bacterial invasion of epithelial cells, metabolism of xenobiotics by cytochrome P450, renal cell carcinoma, small cell lung cancer and rig-I-like receptor signaling pathway (Figure 5).