CCNB2 and breast cancer: The five potential prognostic biomarkers, i.e., Aurora Kinase A (AURKA), BUB1 Mitotic checkpoint serine/threonine kinase B (BUB1B), Cyclin A2 (CCNA2), Cyclin B2 (CCNB2), and PDZ binding kinase (PBK) were upregulated in breast cancer.