CCNB1 (cyclin B1) is a critical cell cycle regulatory protein that controls the G2/M transition during mitosis by forming the cyclin B1-CDK1 complex 1. The protein requires copper binding for proper CDK1 activation, with CCNB1 facilitating copper transfer from ATOX1 to CDK1 to enable kinase function and cell cycle progression 1. CCNB1 expression is dysregulated across multiple cancer types, being overexpressed in hepatocellular carcinoma, breast cancer, colorectal cancer, and lung cancer, where elevated levels correlate with poor prognosis and advanced tumor stages 2345. In hepatocellular carcinoma, CCNB1 is regulated through the SNRPB/FOXM1 axis and contributes to cisplatin resistance via lipid metabolism reprogramming 2. In colorectal cancer, Chk1 induces CCNB1 overexpression, promoting cell proliferation, and CCNB1 knockdown causes G2/M arrest and apoptosis 4. CCNB1 also plays roles in prostate cancer progression and chemotherapy resistance 6. Genetic variants in CCNB1 are associated with coronary in-stent restenosis risk through differential gene transcription 7. Additionally, CCNB1 expression correlates with immune cell infiltration patterns, particularly CD8+ T cells, in intervertebral disc degeneration 8.