MDM2 and neoplasm: The most common mutations in the p53 gene are considered to be missense mutations, leading to the overexpression of oncogenic variants of p53 protein and homozygous deletions of CDKN2A/ARF, which cause degradation of p53 and/or amplification of Mdm2 and Mdm4, further resulting in loss of p53’s various tumor-suppressive activities [80].