More than two functional modules were involved in 19 pathways, such as the cytokine-cytokine receptor interaction signaling pathway, IL-17 signaling pathway, TNF signaling pathway, PPAR signaling pathway and PI3K/AKt signaling pathway (Figure 4B), which may constitute potential key pathways of early NSCLC. The gene discussed is PPARA; the disease is non-small cell lung carcinoma.