Ultimately, through the joint determination of machine learning algorithms and protein-protein interaction (PPI) network analysis, three pivotal features were identified and included in the arthritis diagnostic model: AP-1 transcription factor subunit (JUN), DNA-damage inducible transcript 3 (DDIT3), and vascular endothelial growth factor A (VEGFA) (Figure 4G). The gene discussed is FOS; the disease is Arthritis.