Our findings revealed a significantly higher concentration of vascular endothelial growth factor (VEGF)-A (p = 0.0136), lower anti-angiogenic ratios (sVEGFR1/VEGF-A (p = 0.0208) and sVEGFR2/VEGF-A (p = 0.0068)), and elevated plasminogen activator inhibitor type 1 (PAI-1) (p = 0.0229) in patients with breast cancer localized in the left breast, regardless of the molecular subtype of IBrC. Here, SERPINE1 is linked to breast cancer.