KEGG analysis showed that two clusters were significantly enriched in cytokine-cytokine receptor interaction, chemokine signaling pathway, leukocyte transendothelial migration, osteoclast differentiation, NF-kappa B signaling pathway, rheumatoid arthritis, TNF signaling pathway, complement and coagulation cascades, and IL-17 signaling pathway (Fig. 3d). The gene discussed is TNF; the disease is rheumatoid arthritis.