In this study, C3, CCL21, SLC34A2, C7, ALB, ESM1, ATF3, EGR1 etc. had large fold change, 109 genes (JUN, ALB, EGF, VCAM1, ITGAM, etc.)were located in the three key modules, 70 genes (JUN, ALB, FN1, EGF, VCAM1, ITGAM, FOS, etc.)were nodes in the PPI network with the top 10% of BC value and degree. The gene discussed is C3; the disease is breast cancer.