However, mutation and/or misregulation of p53, HDM2, and HDM4 occur in most human cancers (Toledo & Wahl, 2006), and recent genomic studies have identified an association between 5S rDNA gene amplification with TP53 inactivation in numerous tumors (Wang & Lemos, 2017), further implicating 5S rRNA as a regulator of p53 and putative driver of p53 dysregulation in cancer. This evidence concerns the gene MDM2 and cancer.