KEGG pathway analyses were conducted (Fig. 7E-G), and it is noteworthy that the genes co-expressed with C3 were remarkably enriched in IL-17 signaling, TNF signaing, and NF-κB signaling pathways; the genes co-expressed with FN1 were mainly enriched in protein processing in endoplasmic reticulum, which were all related to the occurrence and development of cancer. This evidence concerns the gene C3 and cancer.