MDM2 and breast cancer: As early as in 1996, studies using immunohistochemistry (IHC) confirmed that high expression of vascular endothelial growth factor (VEGF) and platelet-derived endothelial growth factor (PDGF) were detected in MDM2 overexpressed breast cancer cells, suggesting that MDM2 may be involved in angiogenesis process of maliganancies [42].