Mdm2, also known as murine double minute 2, is a well-recognized oncogene. It codes for a protein that functions as an E3 ubiquitin ligase, with a key role in targeting the tumor suppressor protein p53 for degradation. This interaction forms a negative feedback loop, as p53 activates the expression of the mdm2 gene, and Mdm2 in turn promotes p53 degradation, thus inhibiting p53's ability to regulate cell cycle progression and apoptosis. Mdm2 is involved in multiple cellular processes such as the cell cycle, apoptosis, DNA repair, and oncogene activation through p53-dependent and p53-independent signaling pathways [2,3,4,5,6,9].

Overexpression/amplification of Mdm2 has been detected in various human cancers and is associated with disease progression, treatment resistance, and poor patient outcomes. It promotes cancer growth through multiple means like growth stimulation, sustained angiogenesis, metabolic reprogramming, apoptosis evasion, metastasis, and immunosuppression. In addition, Mdm2 is involved in tumor immune evasion and can lead to hyperprogressive disease in patients undergoing immune checkpoint inhibitor treatment for malignancies. Mdm2 also has p53-independent functions, such as its role as a chromatin modifier, regulating gene expression similar to polycomb repressive complex 2 (PRC2) [1,4,5,7,8].

In conclusion, Mdm2 is a crucial regulator in cells, with its dysregulation contributing significantly to tumorigenesis and affecting cancer patients' prognosis and response to immunotherapy. Understanding Mdm2's functions through in vivo studies, potentially including gene knockout (KO) or conditional knockout (CKO) mouse models, could provide insights into developing more effective cancer therapies targeting Mdm2 [1,4,5,7].