MDM2 is an E3 ubiquitin ligase that serves as the primary negative regulator of the p53 tumor suppressor protein 1. Its primary function involves mediating the ubiquitination and subsequent proteasomal degradation of p53, thereby inhibiting p53-mediated cell cycle arrest and apoptosis 1. The mechanism operates through a tightly regulated autoregulatory feedback loop where p53 transcriptionally activates MDM2, which then binds to p53's transcriptional activation domain and promotes its nuclear export and degradation 12. MDM2 also functions independently of p53, acting as an E3 ligase for other proteins including retinoblastoma protein and various cellular regulators 3. Disease relevance is significant, as MDM2 amplification or overexpression occurs frequently in human cancers, particularly those of mesenchymal origin, effectively inactivating p53's tumor suppressive functions 14. Clinically, MDM2 represents an important therapeutic target, with multiple p53-MDM2 antagonists under development to reactivate p53 in cancers with wild-type p53 5. However, MDM2's prognostic significance varies across different tumor types, making it a complex biomarker 6.