Gene expression enrichment analysis was performed between datasets with low and high candidate gene expression; multiple signaling pathway related to cancer development were all enriched in samples with high C3, or FN1, or C3AR1 expression phenotype, such as JAK/STAT signaling, chemokine signalling, NOD like receptor signaling, FC gamma R-mediated phagocytosis, and T and B cell receptor signaling pathways (Fig. 6F, Supplementary Table S8). The gene discussed is FN1; the disease is cancer.