12 upregulated hub genes (TOP2A, MAD2L1, FEN1, EPRS, EXO1, MCM4, PTTG1, RRM2, PSMD14, CDKN3, H2AFZ, CCNE2) and 4 downregulated hub genes (EGFR, FGF2, BCL2, PIK3R1) might serve as diagnosis and poor prognosis biomarkers in breast cancer in the future by more research validation. Here, CCNE2 is linked to breast cancer.