CDK1 and breast cancer: Among these DEGs, 10 hub genes with high degree of connectivity were selected in the PPI network, namely, CDK1, CDC20, CCNA2, CCNB1, CCNB2, BUB1, BUB1B, CDCA8, KIF11, and TOP2A. The survival analysis found that higher expression of all the 10 genes predicted more worse prognosis for BC patients and coincidentally all of them were overexpressed in BC tissues compared with normal tissues, which suggested that these genes might not only play a vital role in the prognosis of BC patients but also be crucial in the pathology and progression of this disease.