AKT1 and nicotine dependence: KEGG pathway enrichment analysis results revealed that the upregulated DEGs were predominantly enriched in extracellular matrix–receptor interaction, cytokine–cytokine receptor interaction, focal adhesion, PI3K-Akt signaling pathway, and cell cycle, whereas the downregulated DEGs were primarily associated with gastric acid secretion, neuroactive ligand–receptor interaction, chemical carcinogenesis, xenobiotic metabolism via cytochrome P450, and nicotine addiction (Figure 2 and Table 3).