MDM4 and cancer: Regarded as the “guardian of the genome”, understanding the inactivation of the TP53 tumor-suppressor gene is crucial, as it is mutated in over 50% of human cancers and in the other 50% is compromised through biological inactivation by its negative regulators like murine double minute 2 (MDM2) and X (MDMX) or through mutations in upstream kinases [43].