CCND1 and breast cancer: Core targets identified in the protein–protein interaction (PPI) network included ESR1 (Estrogen Receptor 1), MYC (Myelocytomatosis oncogene), HIF1A (Hypoxia Inducible Factor 1 Alpha), EGFR (Epidermal Growth Factor Receptor), VEGFA (Vascular Endothelial Growth Factor A), and CCND1 (Cyclin D1), representing key molecular pathways in breast cancer development and progression.