All of the 10 upregulated hub genes (CDK1, CCNB1, CCNA2, CDC20, TOP2A, CCNB2, MAD2L1, BUB1, KIF11, and RRM2) were dramatically upregulated in breast cancer, whereas five of the 10 downregulated hub genes (ESR1, IGF1, PDGFRB, PXN, and ZEB1) were significantly downregulated in breast cancer. The gene discussed is RRM2; the disease is breast cancer.